Rick:

These are "gas struts", i.e., the force is provided by pressurized gas,
hopefully captured by the various seals in the unit. An inescapable law of
physics states (paraphrased) that gas pressure varies with it's
temperature - pressure rises as the temperature rises and vice versa. This
MAY be the source of your temperature dependent gear extension.

I say "MAY" only because there could be other explanations (bushings
binding, lubrication thickening due to low temperature, etc.) since the
total volume of gas in a strut is quite small and may not see a large
variation in force with the temperature changes you mention. A simple gear
test on jacks while alternately heating and cooling the strut could be
instructive.

Dan Schaefer