ok so this was my work around, unsure if it will work for others.
when you got to three dots button then go to move to next window.
it should open up the split screen. go the the three dots on the top window which should be the unwanted one with no tabs of use.
then hit the exit button.
the app should close and when you reopen it, it should be in the window with all your tabs previously that you actually use.
then go back to the three dots and go to manage windows and close the one that is the unwanted one. and it should hopefully be back to regular browsing.
hopefully this helps others as this has plagued me from time to time for months