Which I’ve also referenced, if you’ve noticed.
Define ‘normal’. 
We’ve actually got an example of problems with it, apparently, which changes the picture entirely.
You meant to say ‘Tyrael’, I assume. And it might, as it turns out, be problematic indeed.
I don’t mind confusion, but reports about problematic mercenaries may indicate actual bugs one way or another, so I wouldn’t completely dismiss the whole matter.
As for Vanndar, getting his golden portrait before the base mercenary card was intended (and haven’t they given base versions of TLK, Diablo and Sylvanas or a compensation of 100 coins to those who pre-purchased them?). Other such instances mentioned above stem from bugs, which itself is an issue.