Thanks for the answers.
The issue was with the "Vanilla Skyrim LOD Billboards" mod, which provided billboards for vanilla tundra and yellow shrubs, among other trees. After removing these files and rebuilding the LOD, the yellow trees have disappeared.
I'm curious about what the ignore parameter does, though. The window dont show any explanation for it: https://ibb.co/hWhRR9P and when I tried it, the landscape didnt change. Do this parameter only applies to statics?
