I haven't yet encountered this issue consciously myself, but others have multiple times. This used to already happen to powerups but with carrots its an even bigger issue. In competitive play we rely hugely on knowing who got the carrot. If 2 flagholders fight for it the outcome of that battle is a huge deciding factor in what happens next. If your flagholder is 1 and your enemies is 3, you will play very defensively, yet if theirs is 1 and yours is 3 you will do the opposite. Later finding out that they actually took the carrot as well is very disruptive to the match's competition obviously.

As far as I know this never used to happen with carrots before. There would be fake carrots which means 1 of the 2 players that took it wouldn't actually be 3, even if his screen would tell him so.

An example: