I first reported this issue with the 12/20 version with Firefox, now it occurs with Chrome/Brave too.
When pasting between tabs, it doesn’t work at all (using any method) unless the number of free measures is equal/greater than the paste length.
i.e. if I copy 8 measures and try pasting into a free measure at the end nothing happens. If I create 7 extra empty measures it works. The expected, and previous non-buggy behavior is additional measures are auto-created and the contents pasted correctly regardless of length (auto add measures is on.)
(EDIT: It seems even when additional measures are available only up to 8 at a time can be pasted so it may be related to line wrapping.)