Hi,
I have serious issues with customizer after update.
I have tested the solutions/troubleshooting you proposed in a former post. My server has 1Gb php memory and I tried with all plugins disabled (no change).
Practically, when I load the X customizer page, my browser gets crazy and the memory in cache keeps increasing until 15Gb+ ! after that I need to close the tab to prevent browser crash. I happens with all major browsers.
Do you have any idea what could cause this memory leak?
Best