I think it may be an Android 10 issue, or at least a Pixel 3 XL issue. I compared MC logs when playing from the Samsung Android 9 tablet vs playing from the Pixel 3 XL Android 10 phone, and BubbleUPnP on the Pixel seems to keep sending Bye-bye events. These don't occur when playing from the Samsung.
0008718: 3404: Sharing Plugins: CHTTPListenerWorker::HandleConnection: Start
0008718: 3404: Sharing Plugins: CHTTPListenerWorker::HandleRequest: UDP: 192.168.86.23: NOTIFY:
http://239.255.255.250:1900*
0008718: 3404: Sharing Plugins: CSSDPWorker::ProcessNotify: ssdp:byebye: uuid:52f295e7-3a52-7667-ffff-fffffdf23e2c::upnp:rootdevice
0008718: 3404: Sharing Plugins: CDLNADeviceConnectionStatus::NotifyReceivedByeBye: Bye-bye from device: BubbleUPnP Media Server (Pixel 3 XL)
0008718: 3404: Sharing Plugins: CDLNADeviceConnectionStatus::SetConnected: Start
0008718: 3404: Sharing Plugins: CDLNADeviceConnectionStatus::SetConnected: Changing connected to 0 for device: BubbleUPnP Media Server (Pixel 3 XL)
0008718: 3404: Sharing Plugins: CDLNADeviceConnectionStatus::SetConnected: Finish (0 ms)
0008718: 3404: Sharing Plugins: CHTTPListenerWorker::HandleConnection: Finish (0 ms)
0008718: 7256: Sharing Plugins: CUDPSocketReader::Accept: Start
0008718: 7256: Sharing Plugins: CUDPSocketReader::Accept: Description: CListenerBase::CListenerBase [UDP]
0008718: 7256: Sharing Plugins: CUDPSocketReader::Accept: Finish (0 ms)
0008718: 1480: Sharing Plugins: CHTTPListenerWorker::HandleConnection: Start
0008718: 1480: Sharing Plugins: CHTTPListenerWorker::HandleRequest: UDP: 192.168.86.23: NOTIFY:
http://239.255.255.250:1900*
0008718: 1480: Sharing Plugins: CSSDPWorker::ProcessNotify: ssdp:byebye: uuid:52f295e7-3a52-7667-ffff-fffffdf23e2c
0008718: 1480: Sharing Plugins: CDLNADeviceConnectionStatus::NotifyReceivedByeBye: Bye-bye from device: BubbleUPnP Media Server (Pixel 3 XL)
0008718: 1480: Sharing Plugins: CHTTPListenerWorker::HandleConnection: Finish (0 ms)
0008718: 7256: Sharing Plugins: CUDPSocketReader::Accept: Start
0008718: 7256: Sharing Plugins: CUDPSocketReader::Accept: Description: CListenerBase::CListenerBase [UDP]
0008718: 7256: Sharing Plugins: CUDPSocketReader::Accept: Finish (0 ms)
0008718: 9248: Sharing Plugins: CHTTPListenerWorker::HandleConnection: Start
0008718: 9248: Sharing Plugins: CHTTPListenerWorker::HandleRequest: UDP: 192.168.86.23: NOTIFY:
http://239.255.255.250:1900*
0008718: 9248: Sharing Plugins: CSSDPWorker::ProcessNotify: ssdp:byebye: uuid:52f295e7-3a52-7667-ffff-fffffdf23e2c::urn:schemas-upnp-org:device:MediaServer:1
0008718: 9248: Sharing Plugins: CDLNADeviceConnectionStatus::NotifyReceivedByeBye: Bye-bye from device: BubbleUPnP Media Server (Pixel 3 XL)