The 'cleanData' method references a possibly null cache item and makes calls on it under certain odd edge cases. Specifically, this snippet of code in the cleanData method is at fault:

if ( id ) { data = cache[ id ]; if ( data.events ) {

In my execution, I've encountered data = null, which causes script breakage. If this is modified as such, no breakage occurs:

if ( id ) { data = cache[ id ]; if ( data && data.events ) {

I'm unsure why the cache is not populated, and this may be a separate issue entirely, but adding this guard prevents against null cache items.