[4.6.0] Problem on Ubuntu 20.04 Mate

[Bristow]

Thank you for this fabulous software!
I have tried to update on 2 Veyon stations to version 4.6.0. My classroom is on Ubuntu Mate 20.04.

Previously, everything was working fine with version 4.5.5-1~focal (PPA repository)

Here is the problem on Veyon Master. I can't see the client computers that have been updated and I can't act on them... Look :

So, I downgraded to Veyon 4.5.6 on these 2 computers and everything is normal again.
Thanks for your help !