Chrome spell check being stupid?

[UnworthyBean]

My chrome spell check has decided it doesn't want to work properly. Words that are definetly spelt right it underlines and comes up with completely irrelevant suggestions for them. Its set to English.

For example, In the post above 'decided' is underlined and it suggestions for spelling errors are:
December
Decaamber
Deca@mber
Decarmber

Any suggestions for fixing it?

Also, I found the suggestions for 'Underlined' quite amusing
Under-lined
Gunderson
Cindermlla
Burlingame

Surely these aren't even words?