Last week, I pulled 411 tier helm from my M+ vault slots and was granted the normal helm appearance only. This week, I pulled 421 ilvl shoulders from my m+ vault, and still only have the normal shoulder appearance. Screenshots here.
Is this how it works now or is it a bug? Can M+ players not get any tier appearance better than normal? That’s not how it worked with Sepulcher.
I am also experiencing this on my Shaman and Priest, both having Heroic item level tier from vault (and Mythic as well) but only getting the normal transmog unlock. Really hoping this is a bug…
Yep. 418 tier gloves in my vault. Got the normal appearance instead of mythic. Disappointing if it’s intentional 
Same. Hope there is an answer and that it is a bug. Would really suck to have to roll for tier we don’t need, just to collect transmog.
Not just that but also obtaining the mythic transmog would require either full clearing mythic, or coming back months/years later instead of being obtainable via m+ and the catalyst like it was in Sepulcher.
I have 415ilvl tier in my vault this week (I know I’m very privileged LOL) and it’s still showing that it’ll only give the Normal tier appearance.
Bug or intended?? 
It appears this was in fact a bug, and as of today’s patch, I logged in and the items have been retroactively corrected to grant the correct appearances.
Hooray!
Unfortunately, they still dont seem to be giving the tiers below its recolor.
This was not the case with Sepulcher or any other vault items previously. You get the item that you get’s appearance and nothing else, unless you upgrade a m+ item to the various breakpoints.