I had this same problem and was able to solve it.

I went into my autocorrect and it appears I had accidentally created an entry for the apostrophe.

When I typed mrm followed by 's, it should have triggered "Mr Manning's" but nothing happened. The accidental autocorrect entered under the apostrophe symbol doesn't trigger, either. It just prevents the thing before it triggering, it seems.

Deleting the accidental apostrophe autocorrect fixed it.

Sorry to revive an old thread, but hope this helps someone googling for the problem!