I found this:
http://www.noshockzone.org/generator-ground-neutral-bonding/
Down a ways it says...
"Contractor-type generators such as your Coleman 5000 are generally G-N bonded internally, which is why it runs your RV just fine. However, many portable inverter generators from companies such as Yamaha and Honda (your EU3000 specifically) have floated Neutrals (no internal Ground-Neutral Bond) since they expect an external G-N bond to happen somewhere else."
I have a contractor type generator vs your inverter type. Is that why your generator caused trouble vs the others that says it works fine?