Mod pack version - 1.16.5

Steps to reproduce -

Enable FTB Chunk claiming in a chunk
Place a Natures Aura Imperceptible Bulder in the chunk
Set up the Builder to place oak saplings on grass (item / block might not matter?)
The block will make a noise as if placing the item but is fails to do so.
(Optional) Disable the chunk claim and the block can now place oak saplings.

You should be able to set it as an ally through FTB Chunks :)

Yes. There were a couple of 'fake players' requesting permission to my claim. Once I trusted them that appears to fix it.