I've tested this with and without other mods, and it seems burrowing behemoths sometimes teleport successfully and other times they warp back to where they came from.

I did not touch that ability table. Did you try with only with the base mod to see if that was an issue? I will try to look into it and see what I am able to figure out.

These are the ability tables that I touched.
cr_unit_passive_electrified_armour
cr_unit_passive_telescopic_lens_implants
cr_unit_passive_weeping_flayers
cr_unit_contact_warpfumes
cr_unit_contact_shocking_revelation
cr_unit_passive_another_takes_its_location_place

at the top of the screen where the growth vat is it shows Placerholder unit instead of units added by this mod but it might be a mod conflict or problem with original mod idk