From here: selling at an inflated price is a violation of the rules, as it constitutes exploiting a bug.
Selling at the normal price (if you don't shuffle items in your backpack) is allowed, and
it seems unnecessary to add anything else to the rules, otherwise you'd have to do that for every bug.

However, it would be helpful to add a link in the rules to Fizmig with a list of bugs.

You see, the thing is, I, for example, consider taking Maxus with one Hydra on auto-battle by a level 1 hero without a book or artifacts to be a bug; some call it a "feature" and apparently use it without any qualms. The same goes for selling artifacts; I repeat, until there is a clear ban in the rules for each bug, it is pointless to present one's opinion as the truth – whether it is a bug or a "feature," and it is also not worth accusing anyone of using them. IMHO.