A dye that responds to pH has two species, each with its own band. pH sets how much sits in each; what an instrument records is their weighted sum. Where the two bands cross, every curve in the family agrees — the isosbestic point.
How far this bath’s colour moves between lights is colour inconstancy. Metamerism is a property of a pair of baths that match under one light and part under another — the thing a dyehouse fails on — and it needs two baths, not one.
Every readout says which light it is under, because for a dye that is the whole question. The swatch is deliberately un-adapted — a bath under illuminant A is meant to look warmer — while L*a*b* is taken against that same light’s own white, so a difference measures the dye moving and not the lamp changing.
The page refused to export until you ticked boxes confirming PPE, an SDS, ventilation and acceptance of responsibility — on the strength of a hazard level it assigned to your dye’s chemical class.