[Hallicrafters] Question for users of LC200A capacitor/inductor meter

[hwhall at compuserve.com]

My brother bought me one of these for Christmas & I've begun playing with it finally. 
I've noticed it seems to have an unexpected (& undocumented) behavior when measuring small capacitance values. If I set it up with a small fixed capacitor of say 20pF, in a few seconds, the displayed value starts drifting downward & will continue until it reaches 0.00pF.A similar thing happens with small inductors, say 1uH.  With larger values like 100pf or 5mH, the drift takes longer to become noticeable.

Is this the usual behaviour for this model?
WayneWB4OGM