Precursors from rares with Ascended tier?
Exotics have always had a chance to produce a precursor out of the forge. It actually has a higher chance to produce a precursor because 4 exotics will always produce another exotic while 4 rares only have a chance to produce an exotic.
To add to that, 4 of the same rarity items have always had a chance to produce an item of the next rarity. Doubt this will change nor has anything been posted about it being changed.
Jade Quarry since Beta