This is probably due to an overworked worker pushed to meet some metric saying something is delivered when it isn't. I'm sure amazon will do everything they can with software using gps, pictures etc to make it harder to do that.
The last time this happened to me, Amazon's CSR told me that "GPS says it was delivered nearby your building." To which I responded that there were multiple suites inside the building. She then asked if my suite had a mailroom, and I repeated that I had a one-room suite.
Indeed they are doing exactly that. I get a notification when the driver is a few stops away from me along with a map. They also take a picture of the package where they left it and it is all visible from the Amazon app.
