If equipment has a question mark next to it then it has a chance of not being what it appears as and instead being a cursed item, equipment rewarded for completing dungeons are always real so you could try that
Hey sometimes the quirks it displays adventurers getting at the end of dungeons aren't actually put on them when returning, I only noticed this later in the game so maybe it's that. I'm on day 95 but my main party barely has any good quirks, pls fix :)