Enchanter stuns are still not working properly on Vaniki. The patch changed them to work up to 55 but they should be working up to 65. This applies to both regular stuns like 'color shift' and spin stuns like 'whirl till you hurl'.
When this was fixed for Vaniki, it was determined not to be a good idea to increase the old-world stun level cap to 65. To add a little about why, originally spells did not have a level cap, they were added later. It's part of why old-world spells can get really weird (like the level 2 mez working up to level 55). The thing is, no one could land a level 2 spell on a level 55 mob because of how spell resists worked before the level cap was implemented (the resist chance took into account the level of the spell). For the specific stuns that were bugged, these had a hard-coded level cap that wasn't in spell data. In fact, the level cap of these spells is different depending on what zone you're in. There are a set of old-world zones flagged for "high level mez and taunt." The Hole, Cazic Thule temple, Plane of Sky, Plane of Hate A and B, Jaggedpine, Nedaria's Landing, and Caverns of Exile (Sol C) allow stuns with affect_cap 0 to land up to level 55, all other zones up to level 52. I don't see anything related to this code other than stun - so the existing comments about mez and taunt probably refer to something that was removed (or they are wrong). I think that ENC are quite powerful on Vaniki and don't need to assist in stun-locking quite as many bosses - that can be left to other classes.
