Google Calendar synchronization delay with a shared mailbox.org calendar

Hello,

I have shared my mailbox.org calendar with my wife, who views it in Google Calendar.

Everything works correctly, but I have noticed that changes made in my mailbox.org calendar (new events, modifications, deletions) are not reflected immediately in Google Calendar.

Is there a typical synchronization delay between mailbox.org and Google Calendar for subscribed/shared calendars?

Is the delay fixed, or does it depend on Google's refresh schedule?

Has anyone measured the usual synchronization time in practice?

Thank you for your feedback.