I’m in two guild’s with resource synthesizers, one in Gilded Hollow and one in Lost Precipice. Until yesterday, the upgrade levels for the two had remained at different levels and I was able to harvest from both guild halls. However, once the upgrades are at the same level, using up a node at one location will remove it from the other as well.
Depending on the originally intended mechanics of the synthesizers one of the situations is a bug.
If I may add my input, in my opinion the most reasonable way for the synthesizers to work is for them to be harvested once at each guild hall (Gilded Hollow and Lost Precipice) per day so you can be collecting both Shimmering and Tenebrous crystals at once.