probable explains why tanks are materializing in your view already shooting as well
If you mean that the tasks go past their update time and don’t auto change then that has been a thing for a long time. easiest thing to do once the time switches over is to jump into a testdrive and then directly back to hangar again and they will update to the new tasks.
If you mean that you played a match and it didn’t progress the task that might just be because the match you were playing hasn’t finished yet if you left early. The tasks only update once the server replay is saved at match end and not when you leave the match.
Tasks often don’t update for a few minutes after a match even when correctly completed - maybe the server replay is delayed for a bit as you suggested.
Exiting and restarting always seems to be long enough for it to fix itself.