Three ~~~ creates unremovable horizontal separator

That is then injected at all carriage returns that follow.


I'd attach a snippet, but I don't see how to.  The line is a double, a heavy line above a thin line, and follows my text wherever I paste it, carrying the problem with it.  Any idea what I am doing wrong?

THANKS 

OH!

Version: 5.0.4.2
Build ID: 2b9802c1994aa0b7dc6079e128979269cf95bc78
Locale: en-US (en.UTF-8)
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