Is an itinerary such as MDT-YYZ-YVR-HNL-YVR-YYZ-MDT all on AC a/c and no stopovers considered cabotage?

I booked this on AC.com last year, but when checking in at the UA counter I got scolded by the TA and he refused to issue me the ticket and claimed it was illegal... of course, my argument was "then explain how I booked this on the web"... so I told him to issue me the BPs up to YVR and that I'll deal with the YVR-HNL segment once I got my ... into friendly territory @ YYZ. Once at YYZ in the MLL I had no problem getting my last segment BP issued...