Here's a couple more pics of that cap.
I did an Autopsy on it
Pic 1 shows the construction, the mica and foil are squeezed between the end connectors, a bad connection here could cause problems.
Pic 2 shows the Mica, notice the black mark on the edge of the Mica sheets, I think this was either Silver migration or some arcing that was happening, either way it doesn't look good and seems to confirm that this one was bad.