Early shaped charge warheads did not function properly quite often. Donald R. Kennedy ("History of the shape charge effect") recalls:
In 1951, this writer was invited to observe infantrytraining at Camp Roberts, California, where it was obvious that the 2.36-inch Bazookaswere, for the most part, failing to detonate high order and form a jet as designed. Instead,most of the rounds were apparently functioned low order from crush-up on the target, asevidenced by the presence of many undeformed conical liners laying about on the test field.Further, the damage to the armor targets usually resembled that produced by a HEP or squashhead mechanism. Even the Army instructors seemed to be unaware that their Bazookaswere malfunctioning. They described the Bazooka's terminal effect as "discharging abaseball sized chunk of metal from the far side of the armor." There was no mention of apenetration hole.
Note that Bazooka projectile was more advanced than PIAT, f.e. it got cone with more acute angle and stronger explosives. There were also some major quality issues with PIAT bombs production, f.e. cone was not attached strongly enough and it moved inside head during transport, there were voids in explosive filler etc. Hence many remains of early HEAT hits could look just like pieces from the first post of this topic.