It's usually the case with updates (expecially the big ones) that the resources in the universe get jumbled around a bit.
I'm not sure to what extent the changes in Stellar Forge for the Odyssey influenced Horizons, but in either case it is safe to assume that the righs got somewhat "reset", hotspots moved, the type of resources in various rings mixed up, etc.
There is, of course, also a decent chance that hotspots simply don't work very well due to some bug.
As for the price, same deal I'd say. LTDs are quite expensive by default so as the market was reset, they returned where they normally sit. As players flood the market again, the price will go down or if they really became so rare (as they should have been and indeed were at the beginning, before this whole hotspot thing) maybe they will stay up.