OSV-7.1
forge 36.2.22

As title, some ores have no problem (mekanism uranium)

But some ores only have the #forge:ore tag (vanilla iron)

Is iron ore supposed to have additional tags? It literally just takes from the original ore and copies them. None of it is hard coded.

Vanilla iron ore has the forge:ores/iron tag.
And mekanism uranium ore in OSV have the correct tag but osmium didn't

Seems like it could be a race condition?

(My English is not good so I apologize if my words sound rude, I really appreciate your work!)

No worries. Hmm, I doubt it's a race condition because most mods don't register tags manually (you're not supposed to). Minecraft usually handles all of that for you and then OSV basically changes the tags after it's done. So, I'm not sure, but I'll take a look at it before 7.2.

I have started working on dynamic tag support for OSV 1.18 and may be able to backport the feature to 1.16. Will update here if so, but things are moving quite slowly these days due to a few major life changes.