[confirmed]Veilstone Amulet grants hexproof

[Korath]

Describe the Bug:
Veilstone Amulet effectively reads, "Whenever you cast a spell, creatures you control gain hexproof until end of turn." So it continues to boost creatures your opponent steals from you afterwards, and it doesn't help creatures you cast or gain control of afterwards.

Which card did behave improperly ?
Veilstone Amulet.

Which update are you using?(date,name)Which type(Duel,Gauntlet,Sealed Deck)
Dev 66e9381 (post-EMN), but it's been broken this way since Onslaught of Awesomeness in September 2013 (and broken differently before that since it was first added in the M13 patch in September 2012).

What exactly should be the correct behavior/interaction ?
Since it's not adding abilities, it should create a single continuous effect, affect creatures that entered the battlefield or the trigger's controller gained control of after it triggered, and not affect creatures that the trigger's controller loses control of after it triggered.

Short of implementing a general can't-be-the-target of system like I've done in Shandalar, I'd suggest making the trigger create an effect that duplicates Asceticism (without the regeneration part) - that is, the effect card continuously adds hexproof to your creatures during EVENT_ABILITIES until it's reaped at end of turn. It still won't work right with Glaring Spotlight, Arcane Lighthouse, Archetype of Endurance, or effects that make creatures "lose all abilities", but it doesn't currently either.

Are any other cards possibly affected by this bug ?
It's essentially the same problem reported here for Temur Charm.