[4.0.1.48] Android Network Capabilities indicate no connection in NAT64 network

REPRODUCIBILITY (% or how often): 100%
BUILD ID = OS VERSION (Settings > About product): 4.0.1.48
HARDWARE (XA2, Xperia 10…): XA2
UI LANGUAGE: English (UK)
REGRESSION: (compared to previous public release: Yes, No, ?): ?

DESCRIPTION:

When in a NAT64 network with DNS64 the network capabilities indicate no connection to Android apps, meaning some of them straight out stop functioning.

PRECONDITIONS:

Have a NAT64 network with working DNS64 I guess?

STEPS TO REPRODUCE:

  1. be in NAT64 network
  2. install Renshuu or Discord
  3. start either app

EXPECTED RESULT:

App works with no issues.

ACTUAL RESULT:

Discord shows a big fat (annoying) banner (significantly reducing the available screen space) saying “Network connectivity limited or unavailable”.
Renshuu shows a connection failure refusing to proceed.

ADDITIONAL INFORMATION:

The same apps work just fine on an Android smartphone in the same network.

Among the Renshuu logcat this can be found:

06-03 21:47:27.797    88   184 D WIFI    : got request NetworkRequest [ TRACK_DEFAULT id=25, [ Capabilities: INTERNET&NOT_RESTRICTED&TRUSTED Unwanted:  Uid: 10048] ] with score 0
06-03 21:47:27.797    88   184 D WIFI_UT : got request NetworkRequest [ TRACK_DEFAULT id=25, [ Capabilities: INTERNET&NOT_RESTRICTED&TRUSTED Unwanted:  Uid: 10048] ] with score 0