Hi @happymaster23,
I've been working on this project since 2012 and I can assure you that it was never possible to get a certificate via validation to port 8080! The HTTP-01 challenge has always required the use of port 80.
Here, you can see people in 2015 complaining about this policy
and here in 2016
I wrote in some detail about this at
Hopefully this will be persuasive evidence that validation to port 8080 has never been permitted!
Anyway, perhaps your setup had some kind of firewall rule or Docker portmap forwarding port 80 to port 8080? Or perhaps your client was actually using a different challenge type, such as TLS-SNI-01 (on port 443)?