And my own darn fault for using platform Y from team X that would release a security update on a Friday. Yes, fix it. But if this isn't a one-off, get off of platform Y.
Are you suggesting delaying security updates because it's Friday? I mean, you can update only on Monday if you so wish, you're unprotected either way.
If platform Y regularly releases security updates on Friday, that's poor management by X and I would reconsider using platform Y. 0-day issues of high severity should be the exception.
Timezones can make it so. It's not necessarily their fault.
Time zones do make things interesting, but weekends are more or less synchronized. (Holidays are not, notably.)