Yes I have. It's very common in some Eastern European countries, where the words stand on their own without embellishment. Jokes come with no intonation-based warnings. Similarily, listening is presumed and doesn't come with colorful Southern European–style cues.
What's infuriating is when seven times out of ten, you eventually say "hey are you listening?" and they respond that of course they're listening, whyever wouldn't you think so? And the other three times out of ten they're actually not listening and they haven't heard a word you've said for the past few minutes, and you have to either repeat yourself or just stop trying to talk to the person.
Acks are important.