FPP (Falco's Prop Protection) was returning true in a CanTool hook causing every other CanTool hook to be forgotten about.
Falco's been around a long time.
Returning true is a rookie mistake.
Make sure the version of FPP you are using is up to date, whether that be using the latest, or if latest is years old, contact Falco to see if he plans on updating.
Oh, and, garrysmod.org is NOT a good place to get releases unless they are put there by the actual author.
Too many times we've seen crap ulib/ulx stuff put there.