1984 245GLT (intercooled), b21ft

Often when I slow down to stop at a light, or slow down and turn at a corner, my oil pressure gauge needle falls to zero and after a couple of seconds, returns to normal. (normal for me is about 3 bar when driving, 2 bar when idling, I think)

In unison with the gauge needle falling, the oil light on the instrument panel flashes on and then off once the needle returns to normal.

I have looked for similar circumstances in the brickboard archives but have not found anything quite the same.

Is this a cause for concern or just an annoyance? Any thoughts?

Thanks in advance,
Märt