A lot of my google contacts are somehow duplicated. The duplicated contacts do not exist on the google server, only in my akonadi database.
This is how the local copy looks compared to the original on google (both taken from akonadiconsole):
Original (edited for privacy reasons):
BEGIN:VCARD
EMAIL:mail.address@mail.server
FN:Firstname Familyname
N: Familyname;Firstname;;;
NAME:Firstname Familyname
NOTE:google
UID:http://www.google.com/m8/feeds/contacts/my.googleaccount%40gmail.com/bas
 e/311a8c008f37b16b
VERSION:3.0
X-GCALENDAR-groupMembershipInfo:http://www.google.com/m8/feeds/groups/my.googleaccount%40gmail.com/base/50e2144c0d753c92\,http://www.google.com/m8/fee
 ds/groups/my.googleaccount%40gmail.com/base/6
END:VCARD

local copy:
BEGIN:VCARD
EMAIL:mail.address@mail.server
FN:Firstname Familyname
N:Familyname;Firstname;;;
NOTE:test
UID:a8478f46-7e98-44e9-908c-f4d07158aaf6
VERSION:3.0
END:VCARD

So it seems the account information gets lost, but the data is still there in my local database.

Reproducible: Sometimes