I heard of premature detonations, but never heard it as a recurring problem.
I know the lead bands on the end of a parrot shell were often shed at the muzzle and killed friendlies posted in front of the guns.
Parrots were forbidden to fire over head of friendly troops for this reason.
The paper machete on a Shenkle wasn’t a problem. It was too light to have any force.
The Shenkle worked very well from the 3” Rifle, or Rodman but the rifling in a parrot worked much better with the lead band . Cole says that even though they shared bore size, union gunners were to use parrot shells in Partot guns, and Shenkle in the 3” Rifle.
I recall he said ther was a battery just south of the copse of trees that were pulled out for lack of ammunition just prior to Pickets advance.
Afterward, it was found that the battery had dumped its shell behind a stone wall to justify withdrawing!😀
I don’t recall what battery, but there are many more stories of heroic defense of positions by batteries! Stuart’s Battery A, 4th US made a heroic stand at the railroad cut in 1 July. They never got the word to retreat.
The defense of Sickel’s position on day two was full of such instances, and I believe everyone has heard of Cushing running his guns right up to the stone wall at The Angle.
