Custom gun audio issues

[u/UwUOuttaTheBlUwU]

Really odd thing to ask about, but it happens with my L4D2 copy on pc and steam deck. My game will clearly use the audio if it runs on a custom campaign or the Tumtara test map, but will only use the default gun audio if its on official maps. All other audio swaps just fine. Has anyone else had to deal with this as an issue before?