This is a pretty quick report, since I don’t really have much to say about it, but it is worth reporting.
I just joined an empty baseplate game, and all of my CoreGui was disabled.
Not just the script-accessible ones - I couldn’t even open the Esc menu. The only remaining parts were the actual chat window which worked as usual, and a small black bar in the top right where the leaderboard was supposed to be. The topbar and Roblox icons were totally missing.
This place had no scripts at all. I also couldn’t open the developer console to check for any errors, since that was also disabled.
Upon rejoining everything behaved as normal:
EDIT: System information:
CPU: Coffee Lake Intel Core i5 8600k @ 3.6GHz
Motherboard: Gigabyte Z370 AORUS Ultra Gaming-CF
Memory: Dual channel 16BG DDR4 @ 3600MHz
GPU: GeForce GTX 1080 Ti
OS: Windows 10 - Build 18363
Roblox version: ? (how do I check this lol)