A popular but frowned upon bug in TFC is setting off a nail grenade below a ceiling or at a wall. When this happens the nail grenade will rise and get stuck inside, causing damage to the whole hallway upon explosion.
There's a Metamod plugin
which fixes this issue to a degree, but it seems limited to separating floor and ceiling, while an enemy who is below a ceiling or door with a stuck grenade still gets damaged from far away.
So here's my attempt at fixing it, it's not perfect but hopefully good enough.
I've used Ramono's Automatic Unstucking
plugin as basis.
fix_ng_bug_enabled - 0 = off, 1 = on
fix_ng_bug_version - The version number of this plugin.