Calendar invitation synchronization issue


I’m quite new to NextCloud (wonderful solution btw !)
Running well but i have an issue/question about calendar invitation.

I’m using NextCloud calendard that i synchronize on my Android Calendar through Davdroid.
Most of my use is done directly on my Android device.

When i’m creating a new entry and adding guests, it’s sending the invitation(s) and they can accept or refuse it.
But i never got the updated status of the acceptation or refusing appearing on the invitation.
It’s always staying on “Not responded”.

I don’t know if it’s a normal behavior or if i’m missing something …

Thanks for any help,