The Bug:

Custom player heads sometimes flash when moving them around in the inventory.

It seems that every time you click whilst a custom player head is held with your mouse cursor, it will flash and appear as the Steve or Alex head for a split second. Please also take into consideration that this doesn't happen all the time and might be quite difficult to reproduce.

Steps to Reproduce:

1. Enter survival mode and make sure that your inventory is empty.
2. Give yourself a custom player head by using the command provided below.

   /give @s minecraft:player_head{SkullOwner:"slicedlime"}

3. Move the head around in your inventory by dragging and dropping it through the use of the mouse cursor, and watch it closely.
4. Take note as to whether or not custom player heads sometimes flash when moving them around in the inventory.

Observed Behavior:

Custom player heads sometimes flash.

Expected Behavior:

Custom player heads would not sometimes flash.