I try crafting the mantle, I have the Attuned Crystal in the irridescent altar, the base materials too. I right click and it starts for a spllit second and then stops. The table says I have enough light and to be sure I have 2 enhanced Celestial Collector Crystals focused on it too, but it still won't craft. Have 4 others I'm going to try and will update if necessary. Same problem with Bootes and Lucerna.

TLDR: after more testing, the bug is that the indicators that you CAN craft the item trigger at far lower starlight levels than are actually required.

shouldn't be far, should be barely on the edge of it. It's an issue with client/server world tick delays for syncing. Might be fixed in a soon version.

But yes, it's an "amount of starlight" issue.

The amount of starlight shown is now more consistent and should display a more accurate value of how much starlight is actually in the altar for crafting.