Heya! This is a weird compat bug with Starcatcher and Distant Horizons (with shaders)
I have the following:
Distant Horizons 2.1.0-a (I am pretty sure I'm stuck in this version for modpack-related reasons)
Starcatcher 1.3.5
No matter what shader I use, I run into this issue, so I didn't feel a need to include any specific shaders
When I go fishing with the Starcatcher fishing rod, after the minigame concludes the visual bug included above occurs. I can fix it by resizing Minecraft's window, but it occurs every time I go fishing.
I spoke with the Starcatcher mod author about this issue and they said it was due to DH updating whenever the GUI scale was changed(?)
So my question is this: Is there anything I can change in the settings of DH to not have this issue?