After creating a custom block and setting an event for it to use replaceitem, the block fails to replace the main hand item. If set to another slot other than main hand such as slot.hotbar, the command still cannot replace the item if the slot targeted is selected by the player.

Steps to reproduce:
1. Create a custom block with an on_interact component that runs a replaceitem event on the player
2. Interacting with the block will replace all slots except for the main hand if targeted.