If a hypothesis is the crash of KB2919355 only indicates prior damage that had been hidden, then it would have been pretty well hidden damage that didn't show in /restorehealth, /scannow, chkdsk with bad cluster and frees space recovery, or in normal day to day operations.
I had no issues with Win 8.1 Pro x64 prior to the KB2919355, and the prior day to attempting 2919355 had run /restorehealth and /scannow with no errors generated during either, as well a chkdsk that evening, again with no errors generated. I had just finished a month long clean install and customization that would culminate in 2919355. I was a day away from doing a WIM of my system since it was customized the way I wanted it and had no errors, with the plan of replacing the Refresh WIM with this custom one.
While prior corruption on some systems may have exacerbated the issues surrounding KB2919355, it isn't the source of the problem.
I had the exact same scenario. No problems until after the failed update. Prior to that time no errors were generated using /restorehealth.