Updating contacts via CARDDAV functions OK on versions 6 and 7.0 , not more on 7.1 releases

I’m a MDAEMON16.5.2 server administrator. Testing different versions of emclient before buying, with the idea to use it as a standard client to interoperate with MDAEMON, in a 1500 user organization environment.

After successfully configuring emclient 6.x & 7.0 via SMTP/IMAP/CALDAV/CARDDAV configuration, and start testing it successfully, after the upgrade to versions 7.1.x, tasks and calendar items still sync OK, but cannot update contacts on the server. “Internal Server Error” occurs. Already tried to “repair” contacts without success.

I have compared LOGS of VCARD request/responses in 7.0.x functioning emclient versions against 7.1.x not-functioning emclient versions, and it seems that VCARD " RELATED" properties, which have " text:" values (in the real contacts these fields have empty values), are the cause. I follow up the extracted VCARD portions of both LOGS, for you to see:

— Functioning OK on emclient 7.0.x:
BEGIN:VCARD
VERSION:4.0
UID:urn:uuid:93cd855f7d464a709c7c03381a5c7985
REV:20170817T135646Z
FN:Arkaitz Arrizabalaga X
N;SORT-AS=“Arkaitz Arrizabalaga”:X;Arkaitz;Arrizabalaga;;
EMAIL;PREF=1:arrizabalaga@domain.com
PRODID:-//MailClient.Contact/7.0.30242.0
END:VCARD

— Internal Server Error event on emclient 7.1.x:
BEGIN:VCARD
VERSION:4.0
PRODID:-//MailClient.VObject/7.1.30453.0
UID:93cd855f7d464a709c7c03381a5c7985
REV:20170817T135646Z
FN:Arkaitz Arrizabalaga X
N;SORT-AS=Arkaitz Arrizabalaga:X;Arkaitz;Arrizabalaga;;
EMAIL;PREF=1:arrizabalaga@domain.com
RELATED;TYPE=assistant;VALUE=text:
RELATED;TYPE=manager;VALUE=text:
RELATED;TYPE=spouse;VALUE=text:
RELATED;TYPE=children;VALUE=text:
END:VCARD

Is there any way to fix this behaviour in the following versions (is it a bug), or is there any way to customize emclient, and force it not to sync these “text:” toxic values ???

Thanks for your collaboration,
Joseba.