With my 52 year old Biology degree I asked my daughter who got a PhD in Chem in 2007 and works in a tox lab If a person using suboxone would not be eligible for a job based on a drug test.
She said no.
The tests for opiates, suboxone, meth etc are individual and separate and actually based on antibodies. If someone DOES claim they were denied a job based on a false positive they could ask for a mass spec test which will confirm or deny the claim.