Golems with the use core wont place blocks or saplings even with all the correct settings. This works fine in a single player world with the same pack meaning its a server issue. There are a number of forms that say it has something to do with Fake-Player issues and server protection plugins. Here are some forums that cover the issue
https://www.reddit.com/r/feedthebeast/comments/2xd1jw
A few of these have solutions that the mods for this server could look into
Thaumcraft golems with the core "use" do not interact with the world as they should · Issue #74 · GreatOrator/TolkienCraftII
Tolkiencraft 2 Version 2.8.7 Issue description: Thaumcraft golems with the core "use" do not interact with the world as they should. If assigned to a chest with saplings and instructed to...
github.com
Thaumcraft Golem Animation Core:Use not work properly · Issue #402 · tastybento/ASkyBlock-Bugs-N-Features
the golem just hold the sapling,and i can hear the sound that the sapling been placed, but the thaumcraft golem do not have the right to place the sapling,so there nothing happens. where can i chan...
github.com
Thaumcraft Golem can't place items · Issue #1763 · ForgeEssentials/ForgeEssentials
FE 965 I had them previously working, so I'm assuming some kind of permission error on my part. That said, server console tosses me the following NPE whenever a use golem attempts to place a sa...
github.com
A few of these have solutions that the mods for this server could look into