strange temporary shorting
From my experience a short blip often means that there is a diode drop from where you're measuring to ground or something similar, if you switch the probes around then the blip won't happen (in the case that it is a diode).

If your multimeter has a digital display it might display the voltage required to get the diode / component to start conducting and hence 'short' it to ground.

I've had this many times when testing and debugging circuits with lots of transistors / diodes.

As a side note as well, if you have some very small resistances in the circuit (>10-20 ohms) then the multimeter might also show that up as a short.