uncapped: Update closed captions only on new tics

src/d_main.c

@@ -881,6 +881,7 @@ void D_SRB2Loop(void)
 
 		// consoleplayer -> displayplayers (hear sounds from viewpoint)
 		S_UpdateSounds(); // move positional sounds
+		if (realtics > 0 || singletics)
 			S_UpdateClosedCaptions();
 
 #ifdef HW3SOUND