Day care error using the debug


I detected an error while i was testing the day care in essentials v17.

1st- I give my pokemon to the day care npcs.

2nd- When i go to the game's menu and using the debug mode to force an egg in the day care, so i can skip the wait until the pokemon give birth an egg normally, this error pops up and crashes the game.

Any ideas on how to fix the issue? Thx and sorry if i my english is terrible. XD