James

A pinned comment on the video correcting the code would be good for the meantime. And a correction in the description.

I have this problem too, thought it was something I did.

> The TrenchBroom Group Hierarchy setting is a bit complicated - TB uses hidden `func_group` entities under the hood to drive its named brush grouping functionality, which doesn't map directly...

Try turning specular to 0 on each light, that solved it for me.