DavDroid doesn’t handle exceptions from weekly recurring appointment correct. The exceptions don’t appear on the mobile phone, but they appear in owncloud, which I use as caldav server. I can provide you with an example ics file, if needed.
Thanks for your efforts, but this is a duplicate of #170.
Please follow up in OwnCloud returns invalid PREF value.
I couldn’t reproduce the problem with this event and other Lightning events are working here, too. This seems not to be related to Lightning, but to https://forums.bitfire.at/topic/1727/nullpointerexception-attempt-to-invoke-virtual-method-void-java-util-calendar-settimezone-java-util-timezone-on-a-null-object-reference. If I only could reproduce it…
Please follow up there.