Some groups simply refuse to show its tasks in my timeline. When I add these task to an older group they appear. But as soon as I move them back or move them to a new group they disappear from my Timeline and My Work.
I have removed any type of filter, so this is not causing the issue.
I learned, that the board settings don’t automatically check any new added group. You actively have to go do that yourself. What a weird default setting to have. You would assume when you add a new group you want it to appear on the type of view.