Trying 0.42.2-beta (and 0.42.3), I noticed that after emitting Ctrl+Tab, the spaces sidebar forces itself to switch to Spaces & sidebar mode when the previous setting was Only widgets. Works for Automatically show and hide sidebar set to both true and false.
The original bug described in this topic is still present for me.
Anytype 0.42.4 fixes the issue with the shortcut not working for me in most cases. However, I sometimes (not consistently, it is hard to reproduce) still get the following error.
When this happens, usually after switching focus from Anytype and back to the Anytype window, the spaces sidebar will force itself to remain open and that is when the shortcut for switching spaces stops working again.
Same here. I sometimes, when the spaces sidebar is disabled and “only widgets” is selected, cannot switch between spaces via keyboard.
It rather selects the next space and shows the spaces sidebar from now on permanently.
This happens after some usage and I cannot find a pattern. But when it happens I have to restart / refresh the app to make it work again. But I also need to hide the spaces sidebar manually again - 2 times annoying 
0.42.4
macOS
I confirm that I can still reproduce this issue in Anytype 0.42.8. I had to switch between open windows several times and always switch back to Anytype several times during the switching. And after a while, the spaces sidebar remains visible and the shortcut stops working.