Force interpolation when timescale != 1.0

src/r_fps.c

@@ -70,7 +70,7 @@ UINT32 R_GetFramerateCap(void)
 
 boolean R_UsingFrameInterpolation(void)
 {
-	return (R_GetFramerateCap() != TICRATE); // maybe use ">" instead?
+	return (R_GetFramerateCap() != TICRATE || cv_timescale.value < FRACUNIT);
 }
 
 static viewvars_t p1view_old;