2 serial keys got activated into the same account

[j u s t i n]

I had 2 copies of a game called Napoleon: Total War. Both are imperial editions. Played on copy 1 for a while, deleted it, and finally decided a year ago that I reinstall it.
I realized too late that I got the copy 2 key and it got activated. I need help on what just happened. Regarding the previous serial key I used and the one I accidentally used.

[Grogwind]

This will show your license linked to your account

https://store.steampowered.com/account/licenses/

I dont belive it is possible to activate the same game twice on the same account. If your sure you have contact support.

[Ogami]

That is not possible. If its the exact same game editon you will get an error message on activation.
Something like "this account already owns the product(s) associated with this key. Do you want to install instead?"

That does not use up the key.

[Kargor]

Yeah, the license list that was mentioned will clear this up. If the activation did indeed happen then it was a different game; if it did not happen then the key is still valid.

[wuddih]

you can check on steamdb.info and the browseraddon which subscriptions you have activated.

it is not super rare that even when the same crap is on the cover, that it does not include the exact same content. one missing item of the followup key activation and the system will take the key. it only will block it as already owned if the user has everything the key would activate.