mkchromecast can't find Nvidia Shield Tv (most of the time)

I want to cast to my Nvidia Shield Tv and mkchromecast can't find it - well, most of the time it can't, but occasionally it works - even though pulseaudio-dlna, Chrome and VLC can find my Shield without problems.

OS: Fedora 31
mkchromecast - from source, master up-to-date
PyChromecast==4.2.3 (pip install -r requirements.txt in a virtualenv)

pychromecast.get_chromecasts(timeout=60) returns an empty list.

I ran the small program from https://github.com/muammar/mkchromecast/issues/301#issuecomment-613255664 from the python interpreter (no time.sleep) and waited, and after around 30s it printed:

[...]
>>> add_service <zeroconf.Zeroconf object at 0x7fd73f8f2e90> _googlecast._tcp.local. SHIELD-Android-TV-e486ff081e1ff8c5d266d5c0359ba385._googlecast._tcp.local. ServiceInfo(type='_googlecast._tcp.local.', name='SHIELD-Android-TV-e486ff081e1ff8c5d266d5c0359ba385._googlecast._tcp.local.', addresses=[b'\xc0\xa8\x01~'], port=8009, weight=0, priority=0, server='e486ff08-1e1f-f8c5-d266-d5c0359ba385.local.', properties={b'id': b'e486ff081e1ff8c5d266d5c0359ba385', b'cd': b'4C57BB4B92E57DF4D5F1AE83B912EA38', b'rm': b'', b've': b'05', b'md': b'SHIELD Android TV', b'ic': b'/setup/icon.png', b'fn': b'SHIELD', b'ca': b'200709', b'st': b'0', b'bs': b'FA8FC83278B2', b'nf': b'1', b'rs': b''})

Mkchromecast just exits:

$ ./bin/mkchromecast 
Mkchromecast v0.3.9
Creating Pulseaudio Sink...
Open Pavucontrol and Select the Mkchromecast Sink.
Starting Local Streaming Server
[Done]
Selected backend: parec
Selected audio codec: mp3
Default bitrate used: 192k
Default sample rate used: 44100Hz.
PID of main process: 27068
PID of streaming process: 27077
 * Serving Flask app "mkchromecast.audio" (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://192.168.1.74:5000/ (Press CTRL+C to quit)
No devices found!
Cleaning up /tmp/...
[Done]
Killed

muammar / mkchromecast

mkchromecast can't find Nvidia Shield Tv (most of the time) #305