Hello,
Iām new to this community, new to Nextcloud and german. So please be patient with me 
I build a new NC11 Server on an odroid c2 following the instructions by Carsten Rieger (Thank you very very much!!)
Ubuntu64 16.04 minimal
php7
mariadb 5.5
Almost everything is running now but iām still in testing.
initial-situation:
admin is sharing calendar āGeburtstageā for the group āFamilieā granting rights to edit.
User imported his Exchange/Outlook-calendar via .ics-file into his private calendar.
So, when User is transferring one of his imported entries to the shared calendar, the entry is no longer visible to User.
admin is able to see and edit this entry, but even updating wonāt reveal it for User.
If User creates a new entry in this shared calendar, or in his own private calendar and shares it afterwards, everything is ok.
If admin creates a new entry in the shared calendar, User handle it without problems.
Has anyone an idea what went wrong?
EDIT:
As i can easily change these few entries by hand (delete and recreate), i decided to push this tread to dev.
Maybe one of you guys is interested in this behaviour?
Iāll wait with the manual changes for three days, so if someone wants me to make some tests for futher investigation: no problem.
Regards and THANK YOU to all developers and supporters! 