Why does 3/4 time revert to 4/4 time sig?

I've been trying to record in 3/4 time but as soon as my mpc does the 3-bar count in and goes through the entire measure, the time sig reverts back to 4/4 time (the time sig on the display reverts to 4/4 too).

does anyone know what's wrong, I'd appreciate the help, thanks

In the "Change Tsig" screen you should have all the bars selected, i.e. not "1-1" but "1-3" in your case.