Legacy Beasts: The best beasts for companions may no longer be able to spawn

I suspect that all beasts with baseline high movement speed (which includes the Quadrilla) can no longer spawn with the Haste Aura mod.

A couple days ago I decided to try and farm an "all damage shocks" and "haste aura" Quadrilla using the "respawn at checkpoint" trick to reset the Quadrilla at the jungle ruins camp (in cruel act 3). After over an hour, I never saw the haste aura once. I checked the antlion charger and diretusk boar at the infested barrens and saw the haste aura a bunch right away.

For science, last night I counted 1,000 resets of the jungle camp. I saw 0 haste aura Quadrillas.

What I think happened:
In the patch from last Thursday (4/10), in the section about monster speed, under Act 1, GGG said, "The Haste Aura Monster modifier no longer appears on monsters that are already fast"

I'm not 100% certain, but it seems very much like that change was not limited to act 1, and it includes Quadrillas as fast monsters. PoEDB does say Quadrillas have the "fast_movement" tag, which supports the theory that they simply disabled the haste aura mod for everything with that tag. That means that if you used the camp checkpoint reset trick to farm a good companion Quadrilla before last Thursday, you may now have a legacy companion that can no longer be found in the game.

Since Quadrillas seem to be among the best companions in the game, and the haste aura mod is certainly one of the most useful mods for a companion, this is actually kind of significant.

And the nature of the haste aura mod is that the biggest problem with it is that the companion can't always keep up with the player, so you pull too far ahead of it and lose the aura buff. For a lot of players, a high movement speed beast with a haste aura is likely the best companion beast you can get.

Obviously this doesn't "matter" in any real sense of the word, but I think its kind of interesting. I can't think of any time GGG has allowed a desirable legacy item to exist mid league, and in this case, it is even something untradable.

Did you find any posts debunking this? My build needed the same traits as what you were looking for so I'm really disappointed if it's no longer possible and people still get to keep their Quadrilla pre-patch.