Hey mate, have you got the no glowing pickups mod installed?
I used to use that mod, ive encountered the same error with enhanced world and entity persistence mod aswell
P.D.O. has an option in the .ini file to disable glowing pickups if you use that mod.
If its either of these mods you should encounter the FFFFFF error when benchmarking upon loading valentine aswell I believe, atleast this is whats happened during my troubleshooting.
The only other mod that I can think of that ive used which has possibly triggered this one is Instant Fast Travel but again I think that was more of an issue of the game trying to load the no pickups mod while entering saint denis or valentine.
Mods to troubleshoot:
No Glowing Pickups
Enhanced World and Entity Persistence
Instant Fast Travel
Otherwise, What mods do you have installed?