Weird highlights when using groups [A9.5, linux, x11, nvidia]

Hello,
I have 16 audio tracks and the selection works as it should.
I select and the selected track is colored. But if I put all 16 tracks in a group and click on the tracks, sometimes one is highlighted, sometimes 2 and even 3 were successful.
When I delete the group everything is fine again. I create a group and it is there again.