Fixing various issues. (#12368)

* Fixing various issues.

* Lights.

code/modules/power/apc.dm

@@ -1411,6 +1411,7 @@
 		if(WIRE_POWER1, WIRE_POWER2)
 			if(!wires.is_cut(WIRE_POWER1) && !wires.is_cut(WIRE_POWER2))
 				shorted = FALSE
+				update()
 		if(WIRE_AI)
 			if(!wires.is_cut(WIRE_AI))
 				aidisabled = FALSE

code/modules/power/lighting.dm

@@ -314,8 +314,11 @@
 	. = ..()
 	SSvis_overlays.remove_vis_overlay(src, managed_vis_overlays)
 	if(on && status == LIGHT_OK)
-		SSvis_overlays.add_vis_overlay(src, overlayicon, base_state, EMISSIVE_UNBLOCKABLE_LAYER, EMISSIVE_UNBLOCKABLE_PLANE, dir, clamp(light_power*250, 30, 200))
-
+		var/overlay_alpha = clamp(light_power*250, 30, 200)
+		SSvis_overlays.add_vis_overlay(src, overlayicon, base_state, EMISSIVE_UNBLOCKABLE_LAYER, EMISSIVE_UNBLOCKABLE_PLANE, dir, overlay_alpha)
+		var/mutable_appearance/M = mutable_appearance(overlayicon, base_state)
+		M.alpha = overlay_alpha
+		. += M
 
 // update the icon_state and luminosity of the light depending on its state
 /obj/machinery/light/proc/update(trigger = TRUE)