thank you for the pointing to this announcement .
Today I have updatet my phone again. I am on RC channel.
The behavior is the same as before.
I open the calebder app
then I click the button on the top right.
then I click on the button "synchronisieren”
when I do so the first time after update I have to log into my Google acount again.
but after that is no sync
when I press the botton again to sync,
it do not sync
when I open the burger menu to see the sync button I see that he is a lot faster than normaly the sync takes time
and there are no synced data
a workaround is to go to system settings and delete the Google acount and than create it there again.
then the message pop in the window that calendar is syncing
then one sync is vallid,
the next one field then again.
there is to say that the sync of the adressbook works without any probkems on my phone
I hope my report of testing helps the nice guys here to fix the calender