Comment 2 for bug 1370288

Looking closer at it, it looks like a misspelled word with a hypen and then any non-alphanumeric character will cause the spell check to not take you to the occurrence. When there is a number or letter immediately after (or before) hyphen it causes the entire "word" to seen as misspelled and therefore allows you to get to word.
SO...
!-aaa OR aaa-! OR aaa-_ won't let you get to misspelled word.
BUT...
1-aaa OR aaa-1 OR a-aaa OR aaa-a will work
I (obviously) didn't try ALL non alphanumeric characters. But that seems to be the gist.