Not compatible with multisite installation.

This can be disabled in the Breadcrumb NavXT settings page. Under the General tab, look for the “Mainsite Breadcrumb” settings, make sure the checkbox next to “Place the main site home breadcrumb in the trail in an multisite setup.” is not checked.

By the way, it really wasn’t necessary to fill out a review and start a support thread (would prefer just support threads, I do tend to reply within a day or so).