Info

• Server version: 1.13.2
• OldCombatMechanics version:
• Server log file: (No logs)
• OldCombatMechanics config file: https://pastebin.com/raw/FV20YcnA

Problem Description

Eating old golden apples prevent players from adding one golden apple eaten to their statistics, preventing progression on the "A Balanced Diet" advancement.

Changing old-golden-apples enabled from true to false fixes the problem.

This is because the eating event is cancelled so custom effects can be applied. I guess a possible solution is to forcibly award the advancement whenever a golden apple is eaten.
A better solution would be to tell the server that the player ate an apple, which I am not sure on how to do.

@northerncarrots This should now be fixed in test build 64. Please test it out, I made it so both player statistics and advancement progress are incremented by the plugin after the event is cancelled.

Extremely sorry for the late answer.
It seems to be working now. Thank you.

There is one more issue (although it does not pose a big problem). Consuming a golden apple in creative mode will still decrease the item count by one.
Vanilla behavior will keep the item count the same when consuming a golden apple.