It seems that a properly set up Astral Sorcery altar (where the crystal can see the sky directly) will on occasion lose the ability to transmute iron ore into starmetal ore.

I'm thinking that it might be related to:

HellFirePvP/AstralSorcery#535

A restart seems to sometimes fix the issue and sometimes not.

Near the end of that issue HellFirePVP mentions:
"Actually finally found the issue for this being related to how data regarding the starlight network is written & read. Unfortunately i won't rewrite the entire section for this for 1.12, but as far as the 1.14 version goes it should be fixed from thereon."

"So. yea. closing this as it won't be addressed from my end for 1.12, will be by-design fixed with the 1.14 internal changes."

I can travel to a different altar and transmute iron ore to starmetal ore, but it seemed to only work temporarily. After testing with restarts I went back and it no longer worked. Another few restarts and it does. So I'm wondering if this is a similar issue.

In creative, I can break and recreate the crystal and it starts to work again.

Here are my logs, I've combed over them and I can't see anything unusual as it relates to Astral Sorcery.
https://mclo.gs/etECbaM

If the issue is similar, and HellFirePVP has already figured out a solution, it might be a prime candidate for a Universal Tweaks fix! I leave that decision in your capable hands, as it's clear you guys have a decent handle on a wide variety of 1.12.2 mod fixes and improvements!