Unlike other blocks (e.g beacons, brewing stands, etc.), you can uselessly put any item on the netherite ingot slot even if the smithing table UI has the netherite ingot outline.
Any item can be placed in the netherite ingot slot on smithing table
You can put any items in any slot of the smithing table
Netherite Ingot frame in last Smithing Table input slot no longer fits for all items, causing inconsistencies with other blocks that support recipes