It seems as though a previous flight, the plane had a display problem. Unless I missed it, that was not mentioned for the incident flight.
The opening paragraph of the analysis would suggest that they had a fully functional aircraft, with the exception of the CA's speed bug.
When analyzing this event, the first thing to note is the fact that having both autopilots become inoperative did not prevent proceeding with the flight in instrument conditions, since the instruments required to carry out a flight of these characteristics were available tothe crew at all times; namely, they had the artificial horizon, altimeter, variometer, anemometer, compass, turn and bank indicator and the engine instruments (intake pressure and engine pressure ratio).
The phrase "proceeding with the flight" makes it sound as though they weren't on standby instruments, but that could just be a translation issue.