Is it possible for the center image to drift from lp to lp?

Lately it seems I'm having to adjust speaker positioning, slightly, to accommodate for "center image drifting".

It does seem to fluctuate somewhat between varying lps.

Could it be either of these things:

(1) I'm a 57 year old male.
(2) The transparency of my system .
(3) The mixing of any particular lp.
(4) Once one's system is revealing enough, is it possible to hear if the center image, ( in the case of a vocalist) moves slightly from one side of the microphone?

I'm hoping for most to come down on number 4.

Thanks.