Fixing PKA mod double installation et similars.

code/modules/projectiles/guns/energy/kinetic_accelerator.dm

@@ -97,6 +97,10 @@
 	for(var/A in modkits)
 		. += A
 
+/obj/item/gun/energy/kinetic_accelerator/handle_atom_del(atom/A)
+	if(A in modkits)
+		modkits -= A
+
 /obj/item/gun/energy/kinetic_accelerator/proc/modify_projectile(obj/item/projectile/kinetic/K)
 	K.kinetic_gun = src //do something special on-hit, easy!
 	for(var/A in get_modkits())
@@ -261,7 +265,7 @@
 	icon_state = "modkit"
 	w_class = WEIGHT_CLASS_SMALL
 	require_module = 1
-	module_type = /obj/item/robot_module/miner
+	module_type = list(/obj/item/robot_module/miner)
 	var/denied_type = null
 	var/maximum_of_type = 1
 	var/cost = 30
@@ -287,6 +291,8 @@
 
 /obj/item/borg/upgrade/modkit/proc/install(obj/item/gun/energy/kinetic_accelerator/KA, mob/user)
 	. = TRUE
+	if(src in KA.modkits) // Sanity check to prevent installing the same modkit twice thanks to occasional click/lag delays.
+		return
 	if(minebot_upgrade)
 		if(minebot_exclusive && !istype(KA.loc, /mob/living/simple_animal/hostile/mining_drone))
 			to_chat(user, "<span class='notice'>The modkit you're trying to install is only rated for minebot use.</span>")
@@ -326,7 +332,11 @@
 	forceMove(get_turf(KA))
 	KA.modkits -= src
 
-
+/obj/item/borg/updgrade/modkit/Exited(atom/movable/AM)
+	. = ..()
+	if(istype(AM, /obj/item/gun/energy/kinetic_accelerator))
+		var/obj/item/gun/energy/kinetic_accelerator/KA = AM
+		KA.modkits -= src
 
 /obj/item/borg/upgrade/modkit/proc/modify_projectile(obj/item/projectile/kinetic/K)