I stocked up with momentary and latching footswitches. Pure coincidence
, the momentary ones are ALPHA M, stencilled 3N1 and are DPDT.
But the feel is exactly as the suspect one. So as the original was
packed full of grease then perhaps just dodgey contact and then no
latency in the electronics, 300mS or so. So far all I know is 200 ohm,
triggers sw action and 27K does not. I think 100nF+100K will go across
the contact and see if it still works and also whether manually shorting
across, 1/10 second or so spacing, still de-latches.

If its dodgey contacts combined with no latency then replacing with
latching or momentary will not make any difference , in time, as the
contact cleanness fails. Then the (design) fault will return, unless
slowing down the electronics. This is going to be a generic fault with
these stomp boxes , Vocalist Live 3, Harman Music, designed in Canada on
the overlay