Which of the following could indicate a malfunction in the primary flight display of the Beechcraft Travel Air BE‑95?

Inconsistent instrument readings on the primary flight display could signify a malfunction. The primary flight display is critical for pilots, as it presents essential flight data like altitude, airspeed, and attitude. Any inconsistency in these readings might indicate a failure of the display or underlying sensors and could potentially compromise safety. For instance, if altitude readings fluctuate unexpectedly without a corresponding change in the aircraft's actual altitude, it could lead to poor decision-making.

Reading consistent flight data and all instruments functioning within normal limits suggest that the display is operating correctly. Immediate responsiveness of gauges merely indicates that the instruments are reacting as expected, which would not be indicative of a malfunction. Therefore, the option focusing on inconsistent readings is key to identifying potential issues with the primary flight display.