Currently experiencing similar, and as expected, flight from BKK-NRT was delayed 30 minutes due to maintenance, pushing connection to under 30 minutes. Just received an email 1.5 hours into the flight, the connection from NRT-LAX is being delayed 40 minutes due to delayed connections. So now I will end up with more time than scheduled on my layover, but still a respectable 1 hour and 10 minutes.
Unsure if it’s our flight in particular, but I know there are at least 2 other people in J and one in F connecting onto that flight as well.