[1.12] Rapid flickering of redstone lamps in City Mash-up causes weird gray visual glitch

Partner Rank: 4

Verification builds: Beta 1.12 RC1

Summary: When a redstone lamp flickers extremely rapidly, it causes the surrounding blocks to have a pure gray texture for a moment. Like the lighting engine is shutting down briefly.

Impact: Abrupt and startling visual glitch

Repro Steps:

1. Download and enter City Mash-up from the Marketplace.
2. Enable cheats.
3. Run the following command: /tp 1471.0 77 -299.5 0 0
4. The lamps in front of you randomly turn themselves off and then randomly turn back on. Observe the issue over time.

Expected Results: Lamps flicker with normal lighting changes to the environment.

Observed Results: Occasional gray glitches https://gyazo.com/d844de3d1131ef9e69599b1eb876f4bb.

Screenshots/Videos attached: GIF linked above.

Notes: None