Granted Passive Skill - How it works?

As far as I can remember, Transmogrification Curse works on every occasion, even on allies that has attachments/support abilities with steadfast (Spontaneous Growth)

Then when I play Stun Turret, I noticed that it doesn't undo the effect of Ellos' Resolve. However, it does undo Moonstalker stealth ability.

So can someone explain to me, how are passive skills granted? Why work Trans Curse work but not Stun Turret since both remove passive skills?

Are passive skills granted every time card is played and then checked at the start of each player's turn? Moonstalker ability seems to be checked only at the start of the turn, that's why Stun Turret can undo it. But attachments seems to be forever in effect as long as it isn't removed or immunized. What about support abilities like Cover of Night (I think it is only check at the start of turn)?

This is my guess but please explain & correct me if I am wrong.

Passive ability removal will remove passive abilities written on the ally itself. In addition to that it also removes passive abilities that have keywords (right now this includes ambush, protector, defender, haste, stealth, meek, hidden, steadfast) and that were granted by other cards. This is why stealth on an ally given by Moonstalker can be removed with Stun Turret. Passive ability removal does not remove non keyword abilities provided by other cards since they are considered not to be on the ally card and are sourced back to the card that provides it. This is why passive ability removal does not remove damage reduction and +1/+1 buff from Ellos' Resolve.

Transmogrification Curse changes the card type from ally to an item, which results in all attachments that specify to be only attachable to allies to be destroyed since they do not have a valid target anymore.

Well explained. Thank you. But I think it is not common knowledge that passive ability removal does not affect non-keyword passive abilities granted by other cards. Maybe you can put this in tool-tips to read while waiting for a game.