fix

code/modules/client/client_defines.dm

@@ -187,3 +187,6 @@
 	var/list/block_parry_hinted = list()
 	/// moused over objects, currently capped at 7. this is awful, and should be replaced with a component to track it using signals for parrying at some point.
 	var/list/moused_over_objects = list()
+
+	/// AFK tracking
+	var/last_activity = 0

code/modules/client/client_procs.dm

@@ -83,6 +83,8 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 			log_href("[src] (usr:[usr]\[[COORD(usr)]\]) : [hsrc ? "[hsrc] " : ""][href]")
 		return
 
+	last_activity = world.time
+
 	//Logs all hrefs
 	log_href("[src] (usr:[usr]\[[COORD(usr)]\]) : [hsrc ? "[hsrc] " : ""][href]")
 
@@ -850,6 +852,7 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 /client/Click(atom/object, atom/location, control, params, ignore_spam = FALSE, extra_info)
 	if(last_click > world.time - world.tick_lag)
 		return
+	last_activity = world.time
 	last_click = world.time
 	var/ab = FALSE
 	var/list/L = params2list(params)
@@ -922,6 +925,7 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 //checks if a client is afk
 //3000 frames = 5 minutes
 /client/proc/is_afk(duration = CONFIG_GET(number/inactivity_period))
+	var/inactivity = world.time - last_activity
 	if(inactivity > duration)
 		return inactivity
 	return FALSE