iCloud calendars changing color randomly

Since i updated my iPhone 11 to iOS 18 the color of all my calendars is changing randomly.

This happens only with the calendars from iCloud. Other calendars don't have this issue.

Whenever i change the colors back, it takes a few minutes and they change again to something else.

Is anyone else having this issue? looks like a problem with iCloud but i don't know how to fix this, not sure it's related to iOS 18 or a coincidence in time.

I already logged to iCloud to change them from there in case it was something on the device but it did not work...

Found also previous comments from 2013, but apparently was an issue from apple, is it happening again?

What can i do to solve it?