DaVinci 17 failed to set the video mode - error

Hi. A new error has surfaced since downloading the final version of 17 after 17.9 beta. After launching a project I get the "Failed to set the video mode" error message. I have a Decklink mini monitor 4k. Because of the error, no image showing in my LG OLED monitor that I use for grading. In previous beta everything was running ok.

Playback on the timeline also very choppy in this version, even in 2K resolution. No such problems in the last beta.

IMac 5K late 2014
Intel i7 4GHz 4 core
32 Gt 1600 MHz DDR3
AMD Radeon R9 M295X, 4 Gt

Big Sur

Have you checked that your monitoring options haven't changed? Also do you have some other software running that might use the I/O?

Monitoring options are same as before. No other software using I/O.

UPDATE - Video monitoring through Decklink came back after changeing timeline resolution from 2K to HD. But strangely it now works also in 2K, UHD, 4K. So, seems it was just some bug.