Why is autocorrect/autocomplete replacing the last letter, not the entire word?

[AC Question]

I have a Droid Turbo XT1254 (great phone). I'm on Android 5.1, build SU4TL-49.

When I am sending texts in Message+v6.3.5 or gmail or several other apps with text boxes, the autocorrect/autocomplete misbehaves SOME of the time, but I can't reproduce it reliably.

The simplest and most reliably reproducible example is the word "I'd". If I type "id" it should autocorrect to "I'd" and it did so until a few weeks ago. Now, though, it usually changes it to "II'd".

Another example is if I type the name "Brandon" and hit space, it sometimes changes it to "BrandoBrandon." This is immensely annoying, partly because it's so unpredictable. This behavior happens when I hit space or if I tap on the correct suggestion (any operation that triggers the autocorrect or autocomplete, even if the word was complete and correct as typed (as above).

Any suggestions would be helpful! Thanks!

 

[Tim1954]

Most annoying how they remember the false corrections. I usually long press the incorrect word and make the keyboard "forget" the word. But I use SwiftKey so it may be a bit different in your device... Worth a try....