Source: Steam Community (opens in a new tab)
Thanks to you guys for catching the bug. Our programmer has been interrogated once again and he has kowtowed, bonbonbonbon.
Fixed the bug where the Collect All Weapons and Activate All Weapons Combos achievements could not be completed under certain circumstances.
Steam update times within 24 hours of this post. Matching dates do not confirm which build it describes.
Build 13642268 · public branch
Steam updated · First observed
Build 13642268 · test branch
Steam updated · First observed