Decoder "MAD" betrayed us on ... / NFSv4 problem?

my media stor is on a NFSv4 share. Uploading tracks works, permissions / ownership are ok. I can play all uploaded sounds in preview, but they don’t play in a stream:
[decoder:2] Decoder "MAD" betrayed us on "/var/tmp/airtime/pypo/cache/scheduler/10.mp3"!
[dummy(dot)3:3] Source failed (no more tracks) stopping output...
10.mp3 is a empty file, 0 Bytes. But of course it isn’t in the file store. Seems copy to pypo/cache/scheduler/ failes somewhere.
any help apprechiated!

This seems like a permission issue with airtime-pypo which copies things to other directories as part of the staging for liquidsoap.

I’ve initialized it again (rm airtime.conf), then rebooted everything and now it seems to work. May have been a local problem, will observe it for a while.