Dungeon Defenders Collections gift copy appeared mysteriously in my inventory

thanks for the info

DD:E always seemed like an odd cash grab. Glad to see they're giving up on it and focusing on maintaining DD while they get DD2 finished.

Oh, thank you I was wondering what happened.

In all seriousness, good move for them to acknowledge the mistake and try to rectify it, via patches, updates and extra copies (even though everyone and their mother has one by now). I'm one who believes that apologies don't necessarily make up for greedy, bone-headed decisions since it's obvious the developers tried to get away with it in the first place, but this is a decent solution.

Collections, game of the Year Editions and DLC stuff in general isn't tracked correctly, so often even when you own it already you still could enter the giveaway. You'd be banned though afterwards if you won. So..., DON'T do it. I recommend to manually add these GAs to your personal GA-banlist (little eye symbol on the right of every GA).

only a few?

Well you got it but, You can restart Steam to force inventory to update.