Based on what you have said, it seems like it should be passive, unless there are circumstances that we don't know about.  Maybe the prior preparer did something incorrectly.  Unless you find out circumstances that make it non-passive, you should treat the rental as passive.

It can still possibly qualify for QBI, even if it is passive.  Although many/most tax preparers will claim QBI for just about any rental, it is my personal opinion that a single rental (with a single tenant) rarely rises to the level of a Trade or Business to qualify for QBI.  But many disagree with me.