Shadowmask overlap scene visualization mode is not displaying the correct result. When there are more than 4 overlapping lights in the scene, the lights that fallback to static are not highlighted as red.

Steps for reproduction:
1) Open the scene t1 or create a new scene (with static objects and more than 4 stationary lights)
2) Switch to `Shadowmask Overlap` scene visualization mode
3) Observe the lights that fallback to static are not highlighted as red

Notes:
- Works as expected in 5.6.0b2 (rev. 7e6b6345748f)
- Regression introduced in 5.6.0b3 (rev. 358ff4ed3952)
- Comparison with the expected result can be observed in the GIF below