push registration doesn't finish in 5.5.2-RC5 comparing to 5.5.2-RC4

Bug description

Push registration doesn't finish in AM, it is finished in mobile phone. In mobile registration is finished, however AM is still waiting and registration is never finished. Second machine with same configuration but version 5.5.2-RC4 works.

Check video at: https://drive.google.com/file/d/1RUNKfSzDNMhHdPhSXjp58W18IlZzLzxB/view?usp=sharing

How to reproduce the issue

1. follow https://backstage.forgerock.com/knowledge/kb/article/a47604373 to create push notification environment
2. connect mobile to internet using wifi-hotspot from my computer which is connected to VPN, so mobile is able to access test environment
3. try to register demo user with service Push-Reg
4. scan QR code with Forgerock Authenticator application (debug.zip)

Expected behaviour

Device should be registered. User should be logged in

Current behaviour

Device is not registered as in 5.5.2-RC4. In mobile device everything seems all right, but procedure doesn't finish in AM and device is not registered - AM is waiting for message from mobile device.