An old bug, which makes the thin line on top of the taskbar disappear and that I reported for 1.31, re-emerged with one of the last updates. I just quote my original report:
Start11 interferes with the appearance of the taskbar without my approval. When the system boots up and the login animation is running, the taskbar looks exactly as I want it (i.e. the Windows default). But after 1-2 sec., Start11 kicks in and you can see some slight changes in color and transparency, the clock shows seconds (which is okay, because that is the one feature I actually want), BUT: the thin border/line at the top of the bar disappears! Despite the fact that I have not enabled the Start11 taskbar and even with unchanged appearance settings (and clock seconds disabled) in the Start11 configuration tool!! [....]
My screenshots in my original post have somehow disappeared, so here are new ones (left = correct, right = bugged):

This got fixed shortly after my report, but since the 1.4x line, the bug re-appeared. I do not know which update exactly re-introduced it, since I do not update Start11 regularly.
I can only repeat what I said back then: please leave the taskbar appearance untouched when Start11 Taskbar is disabled!
EDIT: I forgot to mention that I use dark Windows mode (so: dark taskbar), but light App mode (so: light apps).