Note that “B” in the screenshot was first covered by a thick colored bar (like in your screenshot), but I somehow managed to get it away.
That is the calendar Title/separator; it is supposed to be there and useful when you have multiple calendars.
What I noticed is that I do not have the drag handles (=) to move the tasks around. I think there are some issues with my installation of aCalendar+. (I uninstalled and reinstalled without change in presentation.)
Did you try with -beta2 (but it shouldn’t make a difference)?
Not available to me yet, apparently.
When you edit a subtask, is the parent task shown correctly?
Yes, for ‘B.B.A.A’ I get “B > B.A > B.B.A” beneath it. (Nicely done, BTW, @Matthias-Laabs .)
Do you have root access to your phone? Then you could read the content provider data directly.
Yes, I can activate root access, but actually I currently think the problem lies with my aCalendar+ install. For example, I have no clue why I don’t have drag handles. I have a gut feeling this may be connected to this ordering problem. I should try on another device with a different Android version (tablet with vendor Android instead of LineageOS). Perhaps tomorrow evening…