Minecraft graphic errors?

In Minecraft 1.15.2 with Optifine I always have the following error when I'm under water:

This blue ensures that I can't see well under water. Who knows what I can do?

How can you make such a card in the top right corner?

The mod is called Voxelmap

Are you on a server or in the SP?

To me it looks like an unloaded chunk

This is a server!

Yes, servers sometimes have the problem that chunks are not loaded due to excessive RAM / CPU utilization or insufficient network bandwidth.

No, that's more of a graphic error

Are there any error logs in the log that were created whenever this occurred? And, well, excluded that it is not loaded?

This is not the case with my friends, I have all settings at low!