The bug
When you have a guardian next to another entity and the guardian fires its beam, it brightens the other entity under some circumstances.
The reason
The following is based on decompiled version of Minecraft 1.8 using MCP. All method and class names are the names used in the decompiled version.
The reason why this happens is very likely that the public void func_177109_a(EntityGuardian p_177109_1_, double p_177109_2_, double p_177109_4_, double p_177109_6_, float p_177109_8_, float p_177109_9_)
method of the net.minecraft.client.renderer.entity.RenderGuardian
class disables lighting, culling and blending but does not enable it again after it rendered the Guardian.
Linked issues
relates to
Attachments
Comments


I can confirm this too.

Seems to be fixed for 15w49b and probably earlier

Confirmed for 1.9-pre3, please reopen

Confirmed for 1.12.2-pre2
Confirmed for 1.13-pre8
Confirmed for 18w30b
Confirmed for 18w31a
Confirmed for 18w32a
Confirmed for 18w33a
Confirmed for 1.13.1-pre1
This issue has been fixed in 19w40a.
[media]
Can confirm.