Caves Stop Respawning?

Greetings!

Me and my wife just started playing this game a couple weeks ago and loving it.

We made a small base that had 3 pretty close caves and would hit them for ore every now and then and after a week or so in game we would revisit the cave and everything was respawned. We did this to our local caves a few times however we recently progressed to tier 3 and tried hitting the caves since we haven't in a while.

Oddly enough the only thing that was in each cave was an exotic ore to mine(which wasnt there before) but literally nothing else. But we had abundant resources so we avoided caves after that and moved our small base to a much larger location We must have spent a week or two in game just moving everything over(we even had a lvl 12 buffalo with a bovine harness too) and after we were finally established saw we had almost no resources left. So we set off to the 3 caves by our old base thinking after weeks in game they would be back

Except this time we found nothing None of the caves respawned anything even after such a long period of times....so why did they stop respawninf all of a sudden? And why was the last respawn only 1 node of Exotic ore?

Is there a spawn limit for the caves? I mean each cave respawned atleast 3 or 4 times amd we just got tier 3 so do caves stop spawning once you progress? Or is our game broken ? Any insight you can provide is helpful :)