I made a test here and added the atlas item from map atlases (which is equippable on a trinket stot) and a computercraft turtle (a "normal" block") to the whitelist (keepinventory gamerule is false), and did a /kill command. Only the turtle that was in a normal inventory slot was kept, the atlas that was on trinket slot was dropped.
Can this be fixed?
Fabric 1.20.1
KeepInventoryControl 1.0.1