If you are stating that you have a valid H1-B visa and continue to hold a job with the sponsoring employer, then your re-entry on your H1-B visa should be non-controversial.
If you have quit your H1-B job and intend to relocate to Canada, you should not attempt to reenter the U.S. based on the misrepresentation that you are in valid H1-B status. If you intend to return and get a job, you will need a new sponsoring employer and will need to 'transfer' your H1-B.

