I have a computer controlled hunter killer and devouring one. Whenever they are owned by player 8 i want them burrowed.
Unfortunately they will not burrow at all but a defiler will burrow.
Running ai scripts yielded nothing (maybe using wrong ones?).

Any suggestions?

Since the defiler burrows I think we can rule out missing burrow tech.
Normally comps burrow idle units, if possible.
Maybe it's because they are heroes. Try their regular counterparts or create them burrowed.

Unfortunately there's no way telling them directly to burrow. For unburrowing there is however (order them to themselves).

Regular units solved my problem. Thanks.