I live in Moscow. And use timezone Europe/Moscow. When I sync owncloud to android over davdroid - it’s all OK! But if I sync android to owncloud - event will make with Moscow time plus one hour. I tried with other app - all ok.
We have just verified that the OS X 10.11.6 Contacts app (in combination with OS X Server 5.1.5) is not able to parse correctly folded PRODID lines.
We have reported this OS X Server bug to Apple (bugs #28172308 and #28173106).
I have just tried with our mailbox.org test account and I can’t reproduce that problem.
Are you sure that you didn’t change the data on the server in the time before DAVdroid uploads the contact? In this case, it would be a conflict and the server VCard would be preferred.
Also, please provide steps to reproduce, debug info and verbose logs.