Yes, TLOD is at 400. Parking spot is 581.
At first, I thought it was a conflict with another vendor ... and sure enough I had Gaya Simulations EGLL as I got the Aviator version of MSFS 2024.
I uninstalled iniBuild's EGLL.
I uninstalled Gaya Sim EGLL.
Cleared/Reset my scenery cache.
Loaded MSFS 2024, went to EGLL and got the same colored spikes. So it seems this issue is with MSFS 2024 base content.
EDIT: not a VRAM issue, 5090 with 22GB our to 32GB being used.