Arrow auto gear extension oddness

I was on a training flight a few days ago in a 180 HP Arrow. I was
demonstrating pitch stability. We were trimmed for straight and level
cruise (something like 23 inches and 2300 RPM at 3500 feet) when I
pushed us over into a dive, letting the airspeed climb well up into the
yellow arc.

Here's the strange part; the yellow "Gear in Transit" light came on
during the dive, as if the auto extension system thought we were trying
to land. The gear didn't actually extend, but the light came on and
(IIRC) the warning alarm when off too. I don't remember the exact speed
this happened at, but it was certainly well above Vlo.

Anybody have any idea what might have caused this? The auto extension
system relies on a combination of airspeed and throttle setting, but
both were well outside the normal operating conditions to trigger a gear
extension.