It's exaggerated. I'm from Newfoundland and have little to no regional accent, but still have very slight grammatical and phonetic tells that are apparently obvious to people from elsewhere.

I use more long "O" sounds than people in the US which is apparently obvious almost immediately, and I have some odd grammar whitch apparently singles me out as from NL very quickly to anyone in Canada.

Also, apparently the way I say "thirteen" has a stronger hint of Newfoundland in it than the rest of my speech, at least according to one of my co-workers from Ontario.

It's quite possible that having such a wide ranging family same social circle has simple acclimated you to the various regional differences in dialect.