You should not be hiding / collapsing the Toolbox. That goes against how it is meant to work. Glad you got your specific problem sorted. The Backdrop filter is also a problem and will be in the next update.
It clears up temporarily in your video, but then returns when you scroll back up the page at the end. This indicates it is unrelated to anti-aliasing of the body font.
but after deleting the toolbox (last step) i have no display errors … :-/
Correct, because it was collapsed, as @handshaper stated above:
Which would again point to it not being the font anti-aliasing.