Just to get you updated on the issue reported around mid October. I had a ticket opened with the theme developers, but in the end my brother took a look after mid-November and fixed a flaw in their CSS display code to make it work, which somehow was either nginx- or WPiA-nginx-conf-related for becoming visible. It is still strange that I did not observe this when running on Apache or Caddy2. The issue was solved without touching the WPiA config at all! It is running really well now in Azure, especially since I went for a full W3 Total Cache license, put in Azure Cache for REDIS for everything and set up the auto-scaling. Spot-landing for WPiA on that one - yes, it is pricey, but availability, survivability and scalability are absolutely awesome.