Isigny 
Again from the Duel books pushing what was a politically driven firing trial in order to prove the quality of the armored plate.

Evidence provided by Carey Erickson concludes that the tests were politically motivated to artificially bolster the performance of the US 76mm gun over the 17 pounder gun which was unfairly  marginalized during the tests the Panthers themselves according to the researcher had significant battle damage (burned out, multiple hits, to front plate ,etc.) or were hit many times to lower the plate resistance before the tests were recorded. 

small excerpt:
  Panther Ausf. A tank labeled as No. 1 listed as having a good quality plate was in reality was face hardened (a curious rarity at this point of the war) and took 9 rounds to weaken the plate enough to allow penetration. Evidence also shows that the Panther tank No. 3 had serious battle damage before being subjected to the firing tests which should have excluded it from being tested in the first place. 

Therefore these tests are not an indication of poor quality Panther plate but rather an indication of the politics at the time I suggest a removal or an amendment informing the reader to the nature of the political nature of the tests.