Upgraded from 1.2.1194 to 1.2.1206 and it looks like it's 64-bit now 
The Task Manager is showing the pandoc process when I knit as "pandoc.exe", not "pandoc.exe (32-bit)". I'm also, touch wood, not having any more problems with knitting or notebooks. I'll update if I run into any trouble! Thanks for your patience, Kevin!