Allays summoned with command cannot duplicate

Same cause as MC-253134, the allay's CanDuplicate NBT is not set to 1. Use this command as a workaround:

/summon allay ~ ~ ~ {CanDuplicate:1b}

For this mob, you will need to specify the NBT data if you'd like to spawn with the ability to duplicate.

That's unintuitive, especially since /summon without NBT spawns the full-default of other entities. You'd expect /summon (at least without NBT) to have that tag default to 1b.

Looking at the warden, if NBT is provided, but not the dig cooldown, it immediately digs, unlike when not providing any NBT.

This is fixed as of 1.19.1-pre1. All Allays which have a duplication cooldown of zero will have CanDuplicate set to true regardless of if it was false or not.