This transmog is not show up in my set’s list anymore. The transmog was removed from the characters that had it applied also.
It is a known issue where the account-bound transmog sets (listed below) go missing randomly. Mine keep doing it as well.
They disappear for a while, then come back for a while.  Very frustrating to keep mogs working.
Support article links:
Wendigo Woolies: https://us.battle.net/support/en/article/249292
Cosmetic Helms - https://us.battle.net/support/en/article/17744
Sprite Darter - https://us.battle.net/support/en/article/291576
Renowned Explorer - https://us.battle.net/support/en/article/264950
              
              
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          Yeah, this is disappointing to hear and this needs to be fixed.
They are working on it. This one seems to be surprisingly challenging.
              
              
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          Thank you for the feedback, can’t wait until it is working again!
              
              
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