Tephra
5
The Voidforge does not teach those recipes. On the Isle of Siptah, those can only be learned from vault chests or Schematic Fragments.
Location discovery points are quite slow to trigger and do not cover the entire area. If you visit a discovery location and run through quickly, it is quite possible to completely pass over the point without it triggering. You should move more slowly to give it time to trigger. The discovery points are usually right around the entrance, so take your time moving around the entrance area until it triggers.