could you help to confirm why adding a new UPnP device to the device list causes music playback to be interrupted?
I tried. But I could not reproduce your case.
Playback music with 192.168.24.38. New device 192.168.24.19 appeared around 20:26:01. But 192.168.24.38 continues playback at the last 20:26:05.
2023/09/19 20:25:41,325: UL02288: T037f8: TL18: [SOAP Request]: SOAP request: [GetVolume] to [http://192.168.24.38:60006/upnp/control/renderer_dvc/RenderingControl]
2023/09/19 20:25:41,335: UL02290: T037f8: TL18: [SOAP Request]: SOAP request: [GetVolume] finished.
2023/09/19 20:25:41,336: UL02292: T037f8: TL18: [SOAP Request]: SOAP request: [GetTransportInfo] to [http://192.168.24.38:60006/upnp/control/renderer_dvc/AVTransport]
2023/09/19 20:25:41,349: UL02294: T037f8: TL18: [SOAP Request]: SOAP request: [GetTransportInfo] finished.
2023/09/19 20:25:41,351: UL02296: T037f8: TL18: [SOAP Request]: SOAP request: [GetPositionInfo] to [http://192.168.24.38:60006/upnp/control/renderer_dvc/AVTransport]
2023/09/19 20:25:41,359: UL02298: T037f8: TL18: [SOAP Request]: SOAP request: [GetPositionInfo] finished.
2023/09/19 20:25:41,360: UL02300: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:01 -> 1.0 / 621.0 sec
2023/09/19 20:25:42,340: UL02310: T037f8: TL18: [UPP_WorkerThread]: Polling SOAP log turns to off.
2023/09/19 20:25:42,375: UL02312: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:02 -> 2.0 / 621.0 sec
2023/09/19 20:25:43,387: UL02322: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:03 -> 3.0 / 621.0 sec
2023/09/19 20:25:44,408: UL02331: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:04 -> 4.0 / 621.0 sec
2023/09/19 20:25:45,403: UL02342: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:05 -> 5.0 / 621.0 sec (per 5 seconds)
2023/09/19 20:25:50,411: UL02349: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:10 -> 10.0 / 621.0 sec (per 5 seconds)
2023/09/19 20:25:55,123: UL02350: T0191c: HTTP Server: [192.168.24.38 :43896]: Sent 6291456 bytes.
2023/09/19 20:25:55,401: UL02352: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:15 -> 15.0 / 621.0 sec (per 5 seconds)
2023/09/19 20:26:00,401: UL02358: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:20 -> 20.0 / 621.0 sec (per 5 seconds)
2023/09/19 20:26:01,239: UL02359: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::upnp:rootdevice]
2023/09/19 20:26:01,239: UL02360: T08df4: --> 192.168.24.19 :41168 SSDP NOTIFY: ssdp:alive upnp:rootdevice
2023/09/19 20:26:01,240: UL02361: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC]
2023/09/19 20:26:01,240: UL02362: T08df4: --> SSDP NOTIFY: ssdp:alive uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC
2023/09/19 20:26:01,241: UL02363: T08df4: Processing USN by NOTIFY from: 192.168.24.19 : [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,241: UL02364: T08df4: This is TargetURN: NT: [urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,242: UL02365: T08df4: Target USN found: [192.168.24.19] as [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,242: UL02366: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,242: UL02367: T08df4: --> SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:device:MediaRenderer:1
2023/09/19 20:26:01,242: UL02369: T0965c: Poll device to: [http://192.168.24.19:49152/dmr_lu_2.xml]
2023/09/19 20:26:01,247: UL02370: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:service:RenderingControl:1]
2023/09/19 20:26:01,247: UL02371: T08df4: --> 192.168.24.19 :52781 SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:service:RenderingControl:1
2023/09/19 20:26:01,251: UL02372: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:service:ConnectionManager:1]
2023/09/19 20:26:01,251: UL02373: T08df4: --> 192.168.24.19 :45722 SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:service:ConnectionManager:1
2023/09/19 20:26:01,253: UL02374: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:service:AVTransport:1]
2023/09/19 20:26:01,253: UL02375: T08df4: --> 192.168.24.19 :60100 SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:service:AVTransport:1
2023/09/19 20:26:01,254: UL02376: T08df4: USNMap Record: ( 0) [] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-tencent-com:service:QPlay:1]
2023/09/19 20:26:01,254: UL02377: T08df4: --> 192.168.24.19 :43378 SSDP NOTIFY: ssdp:alive urn:schemas-tencent-com:service:QPlay:1
2023/09/19 20:26:01,255: UL02378: T0965c: Description contains 1 device.
2023/09/19 20:26:01,255: UL02379: T0965c: - deviceType(URN) is target: [urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,256: UL02380: T0965c: Interested service: urn:schemas-upnp-org:service:RenderingControl:1
2023/09/19 20:26:01,256: UL02381: T0965c: - SCPDURL : http://192.168.24.19:49152/dmr_rcs.xml
2023/09/19 20:26:01,256: UL02382: T0965c: - controlURL : http://192.168.24.19:49152/control/RenderingControl
2023/09/19 20:26:01,256: UL02383: T0965c: - eventSubURL: http://192.168.24.19:49152/event/RenderingControl
2023/09/19 20:26:01,256: UL02384: T0965c: Interested service: urn:schemas-upnp-org:service:ConnectionManager:1
2023/09/19 20:26:01,256: UL02385: T0965c: - SCPDURL : http://192.168.24.19:49152/dmr_cms.xml
2023/09/19 20:26:01,256: UL02386: T0965c: - controlURL : http://192.168.24.19:49152/control/ConnectionManager
2023/09/19 20:26:01,256: UL02387: T0965c: - eventSubURL: http://192.168.24.19:49152/event/ConnectionManager
2023/09/19 20:26:01,256: UL02388: T0965c: Interested service: urn:schemas-upnp-org:service:AVTransport:1
2023/09/19 20:26:01,256: UL02389: T0965c: - SCPDURL : http://192.168.24.19:49152/dmr_avts.xml
2023/09/19 20:26:01,256: UL02390: T0965c: - controlURL : http://192.168.24.19:49152/control/AVTransport
2023/09/19 20:26:01,256: UL02391: T0965c: - eventSubURL: http://192.168.24.19:49152/event/AVTransport
2023/09/19 20:26:01,256: UL02392: T0965c: Not interested service: urn:schemas-tencent-com:service:QPlay:1
2023/09/19 20:26:01,256: UL02393: T0965c: Poll service to: [http://192.168.24.19:49152/dmr_avts.xml]
2023/09/19 20:26:01,274: UL02394: T0965c: Poll service to: [http://192.168.24.19:49152/dmr_cms.xml]
2023/09/19 20:26:01,283: UL02395: T0965c: Poll service to: [http://192.168.24.19:49152/dmr_rcs.xml]
2023/09/19 20:26:01,291: UL02396: T0965c: - Target device : [192.168.24.19]
2023/09/19 20:26:01,291: UL02397: T0965c: - FriendlyName : [SSSS-002F6B]
2023/09/19 20:26:01,292: UL02398: T0965c: - ModelName : [XXXX YYYYYY]
2023/09/19 20:26:01,292: UL02399: T0965c: - DeviceType : [urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,292: UL02400: T0965c: - USN : [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,292: UL02401: T0965c: USNMap Update: ( 1) [SSSS-002F6B] [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,355: UL02405: T08df4: --> 192.168.24.19 :54234 SSDP NOTIFY: ssdp:alive upnp:rootdevice
2023/09/19 20:26:01,356: UL02406: T08df4: --> SSDP NOTIFY: ssdp:alive uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC
2023/09/19 20:26:01,357: UL02407: T08df4: Processing USN by NOTIFY from: 192.168.24.19 : [uuid:7f5773e4-1dd2-11b2-bd22-CCCCCCCCCCCCCC::urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,357: UL02408: T08df4: This is TargetURN: NT: [urn:schemas-upnp-org:device:MediaRenderer:1]
2023/09/19 20:26:01,357: UL02409: T08df4: Friendly name: [SSSS-002F6B] (XXXX YYYYYY)
2023/09/19 20:26:01,357: UL02410: T08df4: --> SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:device:MediaRenderer:1
2023/09/19 20:26:01,358: UL02411: T08df4: --> 192.168.24.19 :53344 SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:service:RenderingControl:1
2023/09/19 20:26:01,359: UL02412: T08df4: --> 192.168.24.19 :37404 SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:service:ConnectionManager:1
2023/09/19 20:26:01,360: UL02413: T08df4: --> 192.168.24.19 :51552 SSDP NOTIFY: ssdp:alive urn:schemas-upnp-org:service:AVTransport:1
2023/09/19 20:26:01,362: UL02414: T08df4: --> 192.168.24.19 :47193 SSDP NOTIFY: ssdp:alive urn:schemas-tencent-com:service:QPlay:1
...
2023/09/19 20:26:05,457: UL02605: T037f8: TL18: [UPP_WorkerThread]: Elapsed: 00:00:25 -> 25.0 / 621.0 sec (per 5 seconds)