Help Keyboard issue: backspace scrolls back, only randomly deletes text.

[TzarChasm]

I'm running an unrooted Verizon LG V20, with Android 7.0 (security patch 4/1/17), SwiftKey version 6.6.0.22. I prefer SwiftKey to other keyboard apps I've tried; however, of late I've encountered an extremely frustrating issue in which my backspace key functions randomly as a back arrow: it simply scrolls back through text without deleting it. Sometimes it works, sometimes it doesn't; and sometimes it likes to switch things up mid-word as I am making corrections. I hate, hate, hate this.

This glitch occurs in Chrome, Gmail, and my basic texting app--basically anywhere I can type. I have found no exception so far. Does anyone know how to fix this crap? It makes me want to throw a $600 phone!