Totally normal: the dimensions printed on the sidewall are only directional as true measured width can vary widely based on the specific manufacturer and on the specific rim you're using. I just went down to my bike room and used some calipers on a couple of bikes:
Wheel 1: Rim: Enve SES 4.5AR Tire: Panaracer Gravelking slick, nominally 32mm and mounted tubeless at 41psi. Measured width: 34.45mm
Wheel 2: Rim: Giant SLR-1 Tire Continental GP5000TL, nominally 28mm and mounted tubeless at 76 psi. Measured width: 27.97mm
The Giant rim has hooked bead seats with an ETRTO nominal width of 17mm, which is pretty average for what people commonly use. As a result, the measured width is damned close to the nominal width.
The Enve rim has hookless bead seats and an ETRTO nominal width of 25mm, which is fairly massive compared to most road rims. Also, the hookless configuration allows the tire to bulge out even wider. The result is the measured width of the tire is a lot wider than the nominal width even at pretty low pressures.
This is just two examples, on most of my bikes including road bikes, gravel bikes, mountain bikes and a fatbike the measured width varies a bit from the nominal width.