Generally, every FOTA has a roll-out period. It does not get pushed to every device at the same time.
The rollout period is not fixed but it is not unreasonable to expect at least a two-week period until it has reached everyone. You may have downloaded the manual file each time faster than two weeks.
I would recommend to at least wait 2 weeks after each FOTA, and if you still dont receive it - then please write to us again and we can dig deeper but at this point I am not suspecting a "fota bug" on your particular device.
Thanks!