I tried this, but it didn't work. But ClareLaw1, you got me thinking.
And I think I may have found a solution, not just a cumbersome workaround.
You got me to focus on that last pilcrow, paragraph mark, and that led me to believe that there could have been something wrong with it or by extension all the paragraph marks.
So I replaced all paragraph marks with a section break character, the double S mark, not the code ^b, which search and replace will not accept for whatever reason. Search for all paragraph marks, and in the "replace" box, click on in the "Special" box the section break character, the double Ss, not the ^b code. Replace all paragraph breaks with section break characters.
And then, reverse the process--replace all section breaks with paragraph breaks to get you back to where you were.
I have fortunately not been plagued by this problem for a month or two--until it came up in a new document, and it was happening about every paragraph.
After (out of sheer desperation) doing the find and replace and the subsequent find and replace to reverse the process, I've been working away at the document for pages now and not finding the problem at all. I "think" this is a way of deleting malfunctioning paragraph breaks with fresh ones not plagued by this problem.
I've tried so many other "fixes" that simply didn't work that I'm leery of proclaiming this procedure the (or a) solution, but I wanted to get it out there to all on this thread to see if it helps others.
Save your work, of course, give it a new name, try this, and please report back on this thread. I'm particularly interested in learning if unintended consequences happen . . . Good luck!