%localappdata%\Plutonium\storage\t4\players T4 is no exception so currently doing so may result in odd behaviour / crashes.
In addition SOLO custom zombies may also have some issues as outlined above in regard to it treating it as an online game so this may also have a knock-on effect.
#COMMON FF MOD MENU WAW MODS#
In the meantime please move and load your mods from C:\Users\user\AppData\Local\Plutonium\storage\t4\mods instead and they will work as intended.