Clarify please: Tahm Kench - Stasis or no Stasis?

Okay, so what is up with his W (Devour)?
Champion spotlight said it's a Stasis. Skill descripsion says it's a Stasis. Champ reveal says: Allied Champions: When Tahm Kench devours an allied champion, he renders his ally immune from damage and gains extra movement speed when he heads toward enemy champions. Both Tahm Kench and his edible ally can choose when the latter leaves.
Yet I am 100% certain that allies have died at least 2 times in my belly to Ignite
, and one time to poison.
So then wtf?
Intended or bug? If intended please don't say Stasis, say "becomes untargetable, but DoTs still apply" or something. I would be happier if it was only a bug though.
or a
on my team got
Qed to the face. I
