Update _movespeed_modifier.dm

code/modules/movespeed/_movespeed_modifier.dm

@@ -203,8 +203,9 @@ GLOBAL_LIST_EMPTY(movespeed_modification_cache)
 	// your delay decreases, "give" the delay back to the client
 	cached_multiplicative_slowdown = .
 	var/diff = old - cached_multiplicative_slowdown
-	if(diff > 0)
-		client.move_delay -= diff
+	if((diff > 0) && client)
+		if(client.move_delay > world.time + 1.5)
+			client.move_delay -= diff
 
 /// Get the move speed modifiers list of the mob
 /mob/proc/get_movespeed_modifiers()