Completed Dog Tags Disappered

I have been progressing through my dog tags and completed 51 and started to target another 4. Two days later my completed dog tags have dropped from 51 to 45 with no explanation. No idea which ones have been removed. Add comment to Battlefield Players and 3 others reported the same.

Can't evidence previous dog tags value and when reviewed I can't see any recent ones completed that have disappeared.

Thanks for helping.