Hello!

A mod called Supplementaries adds a new block called the Notice Board. It's like an item frame, but as a block, that can display maps and books.
The problem is that with Starlight installed, the light around it doesn't seem to affect the rendering of the map:

Without Starlight (rendered normally):

With Starlight (even with a lot of light sources, the map is always dark):

Oops sorry I did some testings and you're right, that's specific to Seus shaders (not even Optifine), my bad I close the issue.

It looks like you have a lot more mods added in that second screenshot than starlight...