A few moments ago, I opened a pack of Hearthstone mercenaries. In it, I found I was getting a new hero and as I am only missing one, I assumed it was the one I didn’t have (Ysera). Instead, I found another copy of a hero I already had (Vanndar). Therefore, I thought it might be a mislabeled hero portrait for Vanndar. However, when I checked the hero, there was no new portrait either. I have to say I’m a little confused. Can you explain what happened?
long story short , you gained a Vanndar portait in a past event , that let you play a unowned mercenarie and think you own it , becouse thats not true you end opening the base mercenarie later.
No, I have Vanndar to level 30 already and have had him for quite a while. And the portrait I’ve had for some time too.
that means nothing , look at this screen … i have it lvl 30 , with all task , i play it for long time but still don’t own it ( the last locked portait is the base card ).
And is there just becouse i have the golden portait that is from a event.
https://imgur.com/a/xKY3cFU
This is, as far as I know, quite a frequently asked question or misconception… I’ve written so extensively on it yet that there’s probably not much to add at this moment.
I could, perhaps, sum up another thing and make a long story short: if there’s 50 or more (for higher rarities) coins in any of the 5 items from the packs, then that’s the one with duplicate protection, others can — oh, I am repeating myself after all — contain anything. If, however, all items with coins contain fewer than that (the range is specified in the support article), then there might be a problem.
Actually, that one should count for the puspose of duplicate protection.
Otherwise, though, I concur with your conclusion.
It has been considered ‘owned’ from the very beginning (or nearly), as far as I know. See also above about duplicate protection (although I’m not prepared to trace the original source of that information at the moment, but we’ll consider Old Guardian’s reference of it reliable for now).
yeah your reply and OG video is more techical and more true.
https://www.youtube.com/watch?v=mrCEyuQBCSo
but from normal player prospective what they see is the Oval portait and the Rectangle mercenarie and so they think they get a duplicate mercenarie they already have.
It’s not the duplicate protection that don’t works is that they feel it’s not working.
If there is a real problem we should see multiple reports with multiple mercenaries , instead 98% of reports are becouse of Vanndar , other reports are old ones like the OGuardian case with The Lich King/Diablo etc the pre-release bundles , and there are some new with Tyrande , and in future we will see more Tyrande duplicate bugs … and someone who have only golden Yogg portait becouse of a bug on 23.6 release .
And all of this have the same cause , they are obtainable as portaits before having the base card , and this exception create this confusion
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.
yeah i linked it becouse you referenced it , so other can view it and understand what we talk about directly here if they miss your “written” link that have OG links
yeah
edit: i repost this here too
A quote from someone on reddit
https://www.reddit.com/r/HSMercenaries/comments/vlo2uz/so_i_opened_a_pack_and_got_vanndar_whom_i_already/
If I recall correctly from ZombiesGoNomNom’s stream where he explained how this works after getting the rundown from a dev. Essentially if you somehow obtain a non-base portrait for a merc before the base portrait, then when opening packs the game treats the base portrait as a portrait skin. So your pack rolled a Vanndar skin in that slot and it happened to roll the base version portrait rather than one of the other gold or diamond portraits.
The same is also possible for Tyrael right now for anyone who claimed him from the shop when it was bugged and it was granting the gold/diamond portraits rather than the base portrait.
That make sense and explain why no duplicate protection ( >50 coins ) when it happens.