I purchased 10 items. Most “Deep-Dwellers…” for my warlock. It had much better specs than my level 70 gear. I searched using the “usable items only” filter. These came up as the best options. None of the descriptions mentioned a level requirement. When I got them in the mail (after spending roughly 70k Gold) they all had an obvious line that read “Requires level 80”. Now I’m out a ton of cash. I sold most of them back at a few thousand loss per item but I still have several and the prices have plummeted, as I’m sure others made the same mistake, so I’ve still got items that I spent 30k Gold for that won’t sell for 500. All that along with the losses from reselling the other items. I’m going to have learned how quickly I can get screwed by a bug for around 45,000G.
I just ran into the same issue. Makes sense now why people are paying so much money for the lockboxes. Luckily I only lost a few thousand gold, so I hope you mostly got yours back. I sent a bug report so hopefully they recognize it soon.