Could an Expert pls take a look at this barcode scanning thread and weigh in?
Me and @Peter_A have tracked this barcode problem down to a specific version while we're running different OS variants on different phones, post that version the changelog showed "Camera Permissions Update" and at that point forward barcode scanning became a problem. Anecdotally for me it's when the scanner line started moving up and down on it's own. For me in portrait orientation, for him altogether. An official response would be cool. All of our back and forth is in there with phones, versions, Cronometer versions and update history.
At this point we've both downgraded back to v3.9.2 as everything works normally for both of us with that one, but really shouldn't need to.