I experienced The Multicalender on the website (for me acting as the "new dashboard") recently has a very long delay in showing updates.
After receiving a message regarding a new booking request, it took almost 30 minutes before it shows up on the Multicalender.
(and yes, i refresh the screen regurarly)
I could even manipulate dates (like blocking them), while the booking request for those dates was sitting in the background (Inbox)
Seems to be some synchronisation problem out there ? So be aware "what you see is NOT what you get".
Also happened the other way round: a booking request was retracted, but stays active on the Multicalender for a long time period.
(while it had already disappeared from the listings calendar)
BTW I do not use any syncing / linking with other calenders.