What's the issue you encountered?

BOP isn't the default world type on server even if the config is set to true.

How can the issue be reproduced?

Create a server with BOP.

Logs

latest.log: https://pastebin.com/CAs7XcNc
server.properties: https://pastebin.com/PXhnSYxu
I think the important line is line 26. It says that the world type was injected but the the server.properties still says default.

Mod Version

BOP: 1.15.2-10.0.0.353

As of the latest Forge the config file is no longer necessary. Instead you should set the level-type yourself to biomesoplenty in server.properties.