current inbox messages wont sync between desktop browser and mobile app client

hi, why cant i see my last private message activity on a pc browser? the users im speaking with are in the correct order but only messages from years ago are showing up. i have tried logging back out and in again, clearing browser history, different browsers (waterfox/edge). i primarily use fb on my android phone and rarely use it on desktop these days, must have been a while.

i also may not be explaining my problem properly because i spent nearly an hour looking for a solution on different search engines with no appropriate content, just feeling flustered. thank you.