You did not say if this was a dry filled battery at the time of installing it. It sounds as if it was.
You really should not take a DRY battery out of a box,, fill it with acid and install it in a vehicle without first charging it.
The acid will soak into the new dry plates and I would expect to see the level of the acid fall a bit. If after soaking and charging, if the level is now 1/4" below the tops of the plates, installing it into a vehicle under those conditions would NOT damage the VR and stator.
(On flooded batteries, after adding the acid to a new dry battery, you must charge the battery with a charger before installing it in the vehicle.)
The big question I now have is how did you make up for the partial acid fill. With a NEW battery, the "soak in" difference must be made up for by adding electrolyte and not with plain distilled water.
But based on the limited info you supplied (was battery dry filled, prior filled, dry-filled and not charged first, dry filled and charged prior to install etc) I would say the low level of acid did Not damage the stator or regulator. It sounds like what you experienced is the "normal" fall in level (1/4") I would expect to see as the acid soaked into new plates after filling a dry battery out of the box.
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