Did you try measuring them? For example, take the ones that are actually 124gr, and measure their length with a caliper. I measured mine, and the length were all over the place. So for the same OAL, the volume will change, which makes the inside pressure change, all else being equal. This is due to their irregular shape.
Now add that to varying OAL (I believe the OAL varies a lot because their have a pointy head while the seater of the die is more for round nose, so they don't seat so precisely), and case volume can change a lot. Not enough to be dangerous imho, but enough to impact accuracy.
When I bought these bullets, I also bought 2 boxes of reloaded x-metal ammos. The ammos were labeled 124gr and the bullets 125gr. The ammos were 1.150'' OAL and functionned correctly in my Shadow. If I load ammos with the 125gr bullets, I need 1.06 to 1.07'' for the ammos to function in my shadow. Otherwise they get stuck in the rifling and don't chamber properly. Looking at the ammos, the head of the bullets are different, even to the naked eye. So either they don't use the same bullets to reload their own ammos, or they changed their mold and made 2 batches with 2 different shapes.
Whcih powder/charge do you use with these? I tried HS-6 but didn't like it, I'll probably try titegroup next.