Server showing wrong Phonenumber label


i create an new Contact on my Android Smartphone with 2 phone numbers.
The first Number is labelled as “Hauptnummer” the second as “Zweite Nummer”

At the Server is showing me the Label “Anruf” (for the first Number) and “X-Assistant” for the second phone number.
I don´t know why the Server choose different Label.

My System

Nextcloud 10.0.1
Ubuntu 16.04
Nginx as reverse Proxy
PHP 7.0.13 (FPM)

(no logentries)

Android 6.0.1

related to this issue?

Yes, it’s the same issue.