Weird CoD AW Gold Edition problem PC

Today something very weird happened to me. I played a game of FFA (on a non-DLC map) and I got a supply drop. When I opened it, there was an AE4 inside (I don't know which variant).

I wanted to equip it in a class, but when I chose it, the game opened the Steam library. It showed the page for the Call of Duty: Advanced Warfare Gold Edition, but it said that it was already in my library.

I scrolled down to the text:

Gold Edition now available.

The CoD AW Gold Edition includes the full game PLUS Havoc ..

• My CoD AW shortcut's target is steam://rungameid/209650
• The URL of CoD AW Gold in Steam library is http://store.steampowered.com/app/209650

Also, when I play a private match with only bots, some of them wield the AE4.

I bought the game on DVDs and I don't have the Havoc DLC. What is going on?

EDIT: I went through the game files and now I'm even more confused. I found files named:

eng_patch_common_CORE_mp.ff
eng_patch_mp_URBAN.ff
eng_patch_mp_ZOMBIE_LAB.ff

Core and Urban are MP maps in Havoc DLC, and I assume that zombie_lab is Outbreak because it's an Atlas research lab.

There are also dozens of other Exo Zombies related files. The bots can wield the AE4 because there are files related to dlcgun1 which is AE4.

My Info:

• Location: Croatia
• System: Windows 7 x64 Professional alongside OS X on a late 2014 MacBook Pro
• Steam name: progamer3141