Hello @attila.
Thank you for your reply. As I was trying to get a screenshot, it occurred to me that it won't make the error while Waveforms is in focus. When I leave the app to work in a different app, the message comes up within five minutes. I have Waveforms running on a separate screen, so I'm using it, but with another app in focus. It might be a coincidence. Hope that helps.
I will try the beta version now and get back to you.
NT