Evolving Dehaka while he is “off-map” due to a pack leader being present causes the evolution in question to not be granted while still expending a evolution point. This bug has been previously reported by user Shazamer back in August of '20 regarding a single-level evolution, detection.
In my case, I selected healing aura type I, and further levels could be spent furthering it to types II and III, but no level would add the ability to the command card or benefit units as expected. I killed Dehaka and respawned him with no changes, meaning this is a permanent loss of a skill if tier 1 is taken. I did not attempt this with middle or final tiers of a multitier skill.