I looked at the example with the T-54, and it falls into what I mention. You didn’t hit the turret, you hit the side armor, on top of three additional small bits of armor. With the current mechanic, APDS loses additional left-over penetration after going through a plate of armor, as stated on the changelog I provided. Hitting those two small steel plates on top of having air between them lead to the APDS losing too much penetration to go through the side armor at such a high angle, and made it shatter due to hitting multiple layers of armor, as I have stated is a condition for APDS to shatter.
But really the final takeaway is that this doesn’t show APDS shattering on a singular plate of armor.
The Jumbo upper plate is composed of multiple layers of armor which, again, makes APDS lose more penetration and leads them to shatter if they fail to penetrate.
This is what supposed to illustrate how inconsistent it is.
The 17 pdr does not shatter on the Jumo upper plate, it just does not pen. Maybe 1-2 shot in a 100 shatters. Same with the 83mm. But on the other hand, it shatters on a structural steel box on the side of a ZSU-57-2.