There are differences between boot sector and its backup

I get the message of the title.

Unraid 6.11.3

Looked up in the forum and I found this thread:

https://forums.unraid.net/bug-reports/prereleases/there-are-differences-between-boot-sector-and-its-backup-r1745/?tab=comments#comment-21587

Did what was recommended:

dosfsck -v /dev/sda1

Sorted out most discrepancies, except one.

I runned it again and I get this:

Quote

dosfsck -v /dev/sda1
fsck.fat 4.2 (2021-01-31)
Checking we can access the last sector of the filesystem
Boot sector contents:
System ID "SYSLINUX"
Media byte 0xf8 (hard disk)
       512 bytes per logical sector
     16384 bytes per cluster
        32 reserved sectors
First FAT starts at byte 16384 (sector 32)
         2 FATs, 32 bit entries
   7830016 bytes per FAT (= 15293 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 15676416 (sector 30618)
   1956999 data clusters (32063471616 bytes)
63 sectors/track, 255 heads
         0 hidden sectors
  62654593 sectors total
Checking for unused clusters.
Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
1) Remove dirty bit
2) No action
[12?q]?

 

I used the proper way to reboot the machine, through the option to reboot in the main page.

Why would it be unmounting the FS in a unproper way?

Also, It could be that each time I shutdown or reboot the machine, one discrepancy is added to the list.