Hey Luke,
Just spent way too long with a user trouble shooting errors in their copy data on save project. Turns out the issue was they had spaces after the field names in the "destination field" settings of the EM. They got these by copy/pasting from the codebook.
Since field names can never have spaces, I would like to suggest that either the destination fields themselves, or whenever they are used when copying data, that a trim function get used to avoid this in the future. Specifically since copy/pasting from the codebook is pretty common.
Either way, great module!