[4.3.0.12] Whatsapp doesn't show any contacts

[makarch]

REPRODUCIBILITY (% or how often): 100%
BUILD ID = OS VERSION (Settings > About product): 4.3.0.12
HARDWARE (XA2, X10, X10 II, …): Xperia X
UI LANGUAGE: DE
REGRESSION: (compared to previous public release: Yes, No, ?): Yes

DESCRIPTION:

Whatsapp doesn’t show any contacts. The feature is enabled in the settings menu.

PRECONDITIONS:

newly flashed OS

[makarch]

It seems to be a CardDav issue.

When I save a contact on my phone, it shows up in WA, but if I save in my Posteo address book, it doesn’t