Empty case "stovepipes", right? (Meaning not live-round stovepipes, which can be magazine related.)
I wouldn't find it at all surprising that a pistol which has a slightly longer & heaver slide (approx half an inch longer than the standard P30) might exhibit a little more sensitivity (or intolerance, if you'd prefer) to the dual influences of shooter grip stability and ammunition power levels.
Simply put, you're requiring the recoil forces to move a longer & heavier slide, and the shooter's grip technique and ammunition power levels have to be up to the task to enable the pistol to function within the necessary "timing" window for optimal feeding, extraction & ejection.
A smaller stature person with lesser experience, and a less stable & supportive grip technique (meaning unlocked wrist and less firm grip pressure during a critical part of the recoil impulse) ... shooting light bullet weight loads at the lower end of the power range (budget loads) ... might experience issues like this sooner than might other shooters. Hardly surprising.
Some attention to shooting stance (balance and weight distribution favoring more upper body support to resist movement during the recoil cycle) and wrist/grip technique, and the use of some different ammunition, might help resolve this issue.
Also, as the recoil spring begins to take its intended "set" it might help mitigate "sensitivity" to these shooter & ammo influences.
Retired LE - firearms instructor & armorer