Most CSLA static weapons have this event handler in their config:

GetOut = "(_this select 2) removeAllEventHandlers 'Killed'"

This is an awful idea. This will indiscriminately remove all Killed EHs from any unit that happens to get out of it. Mission EHs, mod EHs, everything. If there is a Killed EH used as part of the weapon's scripting for some reason, you should save that EH's ID to a variable and remove only that EH. A blanket removal of all EHs is unnecessary and dangerous.