Here are my findings. (Done on private toon)
As a quick test I gathered from 6 nodes of herbs in the new zone:
- got 4 Isyeh Grass
- got 4 Isyeh Grass
- got 3 Isyeh Grass
- got 6 Isyeh Grass
- got 6 Isyeh Grass
- got 4 Isyeh Grass
Stopped at 6 nodes, due to fact that I was in fact getting more herbs than I do when gathering ore
Therefore, from what I find, there is not an issue with gathering herbs.
You might just be finding nodes that were not completely depleted, thus not respawned fully.
If anyone else has anything further to add, feel free.