Zombies and Skeletons spawned in any way outside of ominous trials will never spawn with diamond armour

how to reproduce:

set up a repeating command block “/summon zombie” or “/summon skeleton” on normal or hard mode and a mob with diamond armour will never spawn, this is not a great way to test it as a diamond armoured mob would be a very rare event (you could also use spawn eggs, spawners, natural spawns or any other method outside of ominous trial spawners this is just the quickest way)

Expected result: a mob with diamond armour would spawn after a few thousand mobs

Actual result: a mob with diamond armour will never spawn

I’ve attached a screenshot showing the loot table for zombie/skeleton armour from the 1.21.110.23 preview behaviour pack which shows that even if the initial range roll selects copper armour and all the bonus rolls are successful, the rarest armour that could be selected is iron

The most simple way to fix this is to increase the initial range to 3 so that gold armour could be selected from the initial range and then if all 3 bonus rolls are successful then diamond armour would be selected (diamond armoured mobs would however then be slightly rarer than they used to be before copper armour but it is better than increasing the bonus rolls instead which would make them very rare)

this may also affect java edition