Pending->Running, GUI Action fails

Dear all,

we are facing with a strange issue. When a job is executing and the next scheduled job is in pending state (since the previous is still running) then following happens. Currenty executing job finishes, next (pending) job becomes “running” but unable to interact with desktop. All background “stuff” is OK but whenever a click or a GUI action happens it fails. Screenshot created in this case returns “nothing” (null), like if “securedesktop” or whatever is in the front. We can not get rid of this. If we swap the 2 processes then situation is the same: the later job fails. Whenever there is a gap (e.g. 1 minute) between the 2 jobs then they run normally. We have 19.10.1 studio. Is there anybade facing with this issue?
Thanks,

Ernő