Problems with communication stability after update to 1.6 P07

After updating from 1.5P16 to 1.6P07 cee we got severe problems with the stability of the master slave communication. We have about 16 slaves, but the communication to 3 slaves on one hardware brakes in a random time interval.
The liveproxy log on the master shows a lot of following errors:
2020-01-16 10:46:26,162 [40] [cmk.liveproxyd.(67016).Site(XXXXX).Client(72)] Cannot send error message to client: [Errno 9] Bad file descriptor

Anyone any idea where to start fixing it?