Audio problem: When Focker is going back to Chicago the woman who is typing stops moving her hands for a little while the clicking noise is still going.
Audio problem: When Jack is talking to Greg inside the changing room, Jack is saying, "I'll be watching you", but his mouth is still moving saying something else. (00:51:40)
Audio problem: When Jack talks about Kevin's ring, Pam stops drinking and coughs slightly but her mouth doesn't move.
Answer: Who says they had to have been legal adults to date when Top Gun was popular? They could very well have been teenagers and got engaged shortly afterwards. If Teri Polo and Owen Wilson are playing characters that were born the same years as the actors themselves they would have been 17 and 18 respectively when Top Gun was released. If they are playing characters a few years older than they actually are, which is entirely plausible, what Pam says makes perfect sense.
BaconIsMyBFF
I would like to add that a movie doesn't stop being "very popular" soon after the release. In 2000, when I was in middle/junior high school, we actively talked about movies that had been released three or more years before (Forrest Gump, Scream, Cruel Intentions, etc.). A movie from 1986 could easily be popular among a dating/engaged couple and their friends in, say, 1990.