Try reinstalling.
If that doesn't work, make sure that your mod loader is not bugging out. Create a fresh setup
and load ArmA to see if that fixes. Also check your keybinds.
If that doesn't work, open up your userconfig and clean any TFAR/ACE folders. With the clean
downloads you should get the configuration setting for your userconfig.
After all these steps, check for any pop-up errors and memorize them.
Open up the mod folder to find the .pbo or file to check and see if it's there.
It may be a corrupted download which is highly unlikely, but has happened to me before.
If you've tried all these things and it doesn't work, come speak to me cause that's fuckin weird.