@Robert Aldwinckle on forums, is it possible that KB3018943 (a November 2014 IE/Flash upgrade) somehow never installed properly and that this is causing problems installing subsequent IE/Flash upgrades like KB3021953 and rollups like KB3000850? The next question is why DISM is unable to correct the corruption.
@showmethefacts, if you go to your Control Panel, Programs and Features, then click on View installed updates (left navigator) and wait for the entire list to be displayed, can you search for KB3018943 in the box at the upper right? When I checked my laptop (Windows 8.1 64-bit), I cannot find any record of that fix being installed nor does it appear in c:\windows\servicing\packages.