RT 5.0.1 - Update.html broken redirect

Hi all,

I have an instance of 5.0.1 running in a docker container behind an nginx proxy on the same host.
The container runs off the host ip and at port 8787, then the nginx on the host runs off ports 80/443.

Essentially the nginx proxy passes and incoming connections on :80/rt and :443/rt to the container at :8787/rt

Now what’s happening, everything now works from what I can tell, but when I go to update a ticket, I get redirected from:

https://my.domain.example/rt/Ticket/Update.html

to…

http://ip.of.docker.host:8787/rtTicket/Display.html

Does anyone know why this would be?
My configuration:

Set($WebPort, 443);
Set($WebDomain, 'my.domain.example');
Set($WebPath , "/rt");
Set($WebBaseURL , "https://my.domain.example");

RT is hosted out of apache using fcgi from within the container.