I can confirm that this issue still exists in 9.2.5 despite the patch notes saying that it has been addressed.
This happened to me today. I mogged the chestpiece this afternoon. All storebought appearances besides the Eternal Traveler set (Renowned Explorer set, Murloc Satch-Shells) disappeared from my collections earlier this evening but my character still retained the Renowned Explorer chest appearance. However, after mogging another piece it hid the chest and now I can’t put it back.
This isn’t the first time it’s happened to me either.
I don’t know if this was the solution, but I deleted my Cache and suddenly it returned.