From commit e493b10, L187 and L194 of lib/system/model/states.js use context.attributeName, however no attributeName is passed in where it is called here
I think this should be just name.
I can't seem to put together a failing testcase, but _changesToSync has one entry with a key of undefined when making multiple changes.
I too have noticed this problem. I'm not sure if attributeName is intended to be used, if so the key might need to be converted to attributeName. Either way, it would be nice to get this one fixed up.
fixed issue #582