Messages Spell Check Not Working

I have a new MacMini which I transferred my profile/settings over to through iCloud from my previous 2016 iMac. I've found one issue with Messages where spell check doesn't work as it used to. I have all spell check/correction options enabled in Keyboard settings and I've tried disabling then re-enabling without any effect.

My issue is when I mis-spell a word in Messages it provides the red underlining showing the error but doesn't autocorrect, and when I right click on the mis-spelled word and choose the replacement word it doesn't replace the mis-spelled word with what I chose.