Virtualmin bug disables websites using PHP-FPM execution mode

A bug from the last update of hosting control panel Virtualmin (ver 6.07) renders "Service Unavailable" the websites using PHP-FPM execution mode:

 

Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

logs are showing:

 

[Sun Jul 28 11:00:19.583179 2019] [proxy:error] [pid 11605:tid 140145000912640] (111)Connection refused: AH00957: FCGI: attempt to connect to 127.0.0.1:8021 (*) failed
[Sun Jul 28 11:00:19.583228 2019] [proxy_fcgi:error] [pid 11605:tid 140145000912640] [client 80.110.94.10:38808] AH01079: failed to make connection to backend: localhost

Quick check and Apache is working, serving static content. PHP-FPM status is ok, running. My first option was to try to reset the execution mode, maybe it is just a glitch, I've cycled between CGI wrapper and PHP-FPM. The website started to load. I did this for all of them.

 

 

After some more research I found that the recent update of Virtualmin (ver 6.07) has a bug that scrambles the ports from Virtualhosts and PHP-FPM pools when the function re-check configuration is run:

 

Fixing port clash for PHP-FPM version 7.0.4

Instead of being just a verbose informative check, it modifies the configuration files so the connection between Apache and the PHP-FPM pool is not available anymore.

For the moment I have all the websites running in CGI wrapper, even if the impact on performance and resources is there:

 

 

Better to have a slower site than an offline one.