The problem seem to be that eM Client 3 stores "PHOTO;ENCODING"s in a different format than Apple. The crash logs shows a stack trace shows:
ABVCardLexer nextUnicodeStringStopTokens:quotedPrintable:trim:
ABVCardLexer nextStringInEncoding:quotedPrintable:stopTokens:trim:
ABVCardLexer nextStringInEncoding:quotedPrintable:stopTokens:trim:
ABVCardLexer nextStringInEncoding:quotedPrintable:stopTokens:trim:
eM Card creates the record:
PHOTO;ENCODING=“b”;TYPE=“image/jpeg”;X-ABCROP-RECTANGLE=ABClipRect_1&0&320&640&640&
Apple’s contact clients creates records like these:
PHOTO;ENCODING=b;TYPE=JPEG
The format mismatch and the stack trace makes it pretty clear what is going wrong. Deleting the encoded photo from the card created by eM Client stops the iOS and Mac OS contacts clients from crashing.
I have the complete CardDAV log for this problem if more information is required.
The server is DAViCal 0.9.9.3.