Game not tracking buckets of tropical fish when breeding axolotl

When breeding Axolotl, the game is not properly tracking the amount of buckets of tropical fish you used. 

 

On the server i play on, ive bred at least 100 axolotl, but the statistics screen only shows me having used 42 buckets of tropical fish.

 

To replicate, start a world, and breed some axolotl, then look at the statistics screen.