Selection renders without colors on server

[Sharparam]

Mod works fine when I use it in a singleplayer world. When I go on my server, the selection renders but it's all gray, despite colors being configured (as the default).

Screenshots:

Both my client and server uses worldedit-forge-mc1.12.2-6.1.10-SNAPSHOT-dist.

Screenshot of it working in singleplayer:

As this is a client-side mod, what on the server would affect it like this?

Edit: I noticed just now that depending on my location relative to the selection and which direction I'm looking in, it does render with colors. This might mean that the bug happens in SP as well but I just happened to always look in a way that it didn't manifest. Still very strange.