Yes, of course!
I'm looking at the same caption in PM5, which highlights the errors and PM6, which doesn't.
Weirdness on further testing on the same caption: if I make a change to the caption in PM6 and add an error, the newly added error is highlighted, but existing errors remain unhighlighted. Further, if I take a word that is misspelled and not highlighted as such, copy the text and paste it in the same caption field, it DOES highlight the newly pasted erroneous word, but the existing misspelled word remains unhighlighted.
Shall I message you wish some screen grabs or send you the caption template directly or something?
Ta
Joel.