The bug may have been fixed from hellfire-pvp, however Direwolf20 is very unlikely to update his pack anymore l, so the bug remains. In direwolf20 if you try to discover a constellation it instantly crashes the game as a fatal error and there is no other way around this issue.
I asked previously...
Item: Scroll of Written Expertise
Item ID: astralsorcery:itemknowledgeshare (#8273)
Stack Size: 1
Reasoning: It is the only way around discovering constellations for Astral Sorcery in Direwolf 1.12.2 and also possibly some other packs as well.