Orichalcum Nodes Going Missing - PoF

My friend and I were collecting Granite for the funerary collection achievement, we started on opposite ends of the map in the beginning and we marked Orichalcum Nodes for each other so we could get them as a reminder after we met up. When I reached him, the Orichalcum nodes he mined were already bare for me even though I had never seen them before.And vice versa, the two I marked for him were seemingly bare as well even though he had not mined them either. Other nodes we came across with each other were fine though, but some how it was like we mined each other's nodes.

As fas as I know: normal nodes do respawn/move periodically, even during the day. Maybe you took "too" long and the nodes switched places with ones you already have mined. But that is just a guess.