Undefined VBlank interval on Ubuntu 20.04 with second display, Radeon 5100 card

Hardware
,
21

3 more licenses:

License key:TG745-67X3M-JKWMJ-RAH9T-62SD5-AC9GD
License key:6CRYZ-52D2F-5VKP7-FKCTP-Q9945-ZGPT2
License key:5DMAQ-UEB7R-7SFJ3-ATZFW-FGPP8-22E6C

Thanks
Steve