Metamerism.

Two colors are metameric when their spectra differ but their tristimulus values agree, which is the CIE definition: spectrally different color stimuli that have the same tristimulus values in a specified colorimetric system. Change the light and the agreement collapses, because the two surfaces were never returning the same shape of spectrum in the first place. This is the everyday reason a sample approved in the booth is rejected in a showroom, and it gets worse the further the reproduction is from the original colorant set: a Pantone ink matched with a process build, a sublimation print matched to a pigment print, a screen-printed solid matched to a DTG build. The instrument will not warn you, because a Delta E measured under one illuminant says nothing about how that pair behaves under a shop's LED panels or a customer's window. The fix is procedural rather than technical: put a second illuminant into the approval and look at target and sample under both before anyone signs, or accept that the reprint decision belongs to whoever is standing under the worse light.