I believe the 1% drop rate might have been for the original version of them. 10% chance for an ancient (10% chance) to roll primal. But that was when they weren't perfectly rolled ancient items, but rather were an item that could roll EVEN HIGHER stats than a regular ancient. Basically, primal ancients were originally meant to be to ancients as ancients were to regular legendary items when they were first introduced. Their worst stats would be better than an ancients best stats.Quote from BagstoneThe 1% droprate never went to live, it was only 1% in the very beginning of the PTR when ancients were introduced. Some people kept track over hundreds of drops (there were spreadsheets shared a while ago on Reddit) from which we believe it to be something between 0.2% and 0.4%, though it seemed to have converged towards 0.2%-0.25%. Do you have a source for the .3% datamine? That'd be interesting.
They probably nerfed the drop rates as they no longer became necessary.