You may be onto something there — if they were doing a practice CAT 3 (weather was VMC) then signal interference to the ILS or an internal malfunction (one of the radar altimeters, possibly) could cause a pitch-over. The pilot could simply disconnect the autopilot and land, but may not have done it in time. From the looks of it the airplane may have been only about 100 feet low.
ILS 28L NOTAM....G/S AND DME OTS. Can’t do a practice autoland.
If something knew it failed, he should have gotten a single land alert. Maybe he did, but too late.