This thread has been going on for years and this is not the only thread and there are others on other forums.
There is NO SOLUTION as yet because it needs MS to get off their bums and sort it, it must be a certain combination of keystrokes brings in a a form of keyboard shortcut. They put in so many ways of doing the same thing that they MUST overlap and this is
what you get, be good if you could switch them all off except the ones you WANT to use as I think that will end a lot of 'bugs'!
I said before those of us who have experienced it need a SOLUTION not a work around.
Thankfully I've not had it recently but rebuilt several templates so maybe I've left it behind, - until next time!
If you read back you'll see many posts are repeats of previous 'advice', please read the thread and not make repeat posts as that gives us all an email alert for a wasted trip back here.