If the PM is hands off, it can work, but they have to truly acknowledge that they cannot do much more than deal with the resource scheduling and paperwork and leave the tech stuff to the technical folks.
One of the best PMs I ever worked with did this flawlessly, the only downside is that occasionally one of the project team gets pulled into a manager discussion.
The other dozens of this type of PM I have encountered half-listen to the tech details and go off promising things and making tech decisions. The absolute worst I ever had required me to explain the entire project at least once a week in one of the status meetings because she couldn't understand why we were doing the work we were doing at some point.
People that can do PM without the tech background well are VERY rare.