Gregor's latest Huben pistol video may be helpful. What Gregor describes may be adjacent to the cause of delayed firing, described above.
Relevant section is just over 4 minutes into the video:
Otherwise it sounds like a tight fitting projectile
with a long bearing surface, that is not able to gain enough starting velocity to swage fully into the rifling, but comes to a stop just partially into the barrel. If this is the failure mechanism, then projectile hardness will also factor into the go/nogo equation.
Looking at an image of a mangled projectile indicating misalignment between mag chamber and barrel bore, the question is; did this misalignment occur before that shot; or as a result of partial mag rotation after the shot where the projectile was not fully expelled?
The above speculation makes more sense, if we consider that a Huben mag operates more like a revolver cylinder, than a rotary mag in a 10/22. Bullets leave the chamber mouth of a revolver cylinder with significant velocity; as do projectiles leaving the chambers of a Huben "magazine". That said, if there is a "mag" indexing problem before the projectile is fired, all bets are off.