Incorrect AppService VNet Private Ports reported to application. *Application unusable*

Question

I'm using Private Ports feature in my AppService connected to VNet by setting vnetPrivatePortsCount

I read the value of WEBSITE_PRIVATE_PORTS environment variable on app service startup and bind to those ports. The ports are not supposed to change during the runtime, but they do in two app services hosted in East US 2.

I have the same setup in an European data centre and the ports are not changing randomly.

I've added logging in my application code that reads WEBSITE_PRIVATE_PORTS environment variable every second, and it constantly reports one set of ports. But when I go to Kudu console, the environments variables section shows a different set of ports in this variable!
Another difference I've noticed is that the AppServices that work correctly report WEBSITE_PLATFORM_VERSION = 99.0.7.639 in Kudu, while the AppServices where invalid ports are reported to the app are running WEBSITE_PLATFORM_VERSION = 99.0.10.793

Repro steps:

1. Open Kudu console of a stopped AppService and note the value of WEBSITE_PRIVATE_PORTS environment variable reported on Environment page (eg. 20006,20007),
2. Start AppService and note the value of WEBSITE_PRIVATE_PORTS environment variable that application obtained (eg. 20008,20009),
3. Refresh Kudu console of a running AppService and note the value of WEBSITE_PRIVATE_PORTS environment variable (eg. 20006,20007)

Ports reported to the application are different than the ones reported in Kudu and actually opened in the firewall. Therefore it is impossible to communicate with the application from within VNet, as the ports that the application binds to are not accessible.

How can I report this issue to Microsoft? I don't have a support subscription and don't feel like paying Microsoft for the priviledge of reporting issues with their services.

UPDATE 24 Jan: Our Switzerland North AppServices stopped working today after they were upgraded to version 99.0.10.793. It's clear that version 99.0.10.793 of AppServices platform introduced a bug in VNet integration.