I notice this a lot with soft/old/worn pads. I think that old pad sensors can be a culpret as well, but yes, there is quite the bounce required on these types of pads.
Really, for $20 or $25, you should prolly buy a set of pads if it's that bad.
Everytime I get an older MPC, or any older gear for that matter, the first thing I do is open it up. (And every MPC gets new pads)
Have a can of Compressed Air handy, Deoxit Gold, some alchohol, not booze tho

, (Preferably denatured as upposed to rubbing alchohol which will leave residue),
Some Q Tips (Quality ones that aren't all fuzzy and strandy), and I deoxit all the PBNO's (Buttons), all connector contacts, etc.
So often, things are jacked because of bad connections, this can go for the Pad Sensor contacts (My buddies 2KXL lost it's entire top row, cleaned it and has been perfect for 6 months),
Screen, all buttons, power connections, etc. (Any slide in ribbon connections are especially crucial, for some reason they seem to corrode easily, and RAM contacts, same kind of thing)
(Careful with the contacts to the screen itself.) I wouldn't screw with that one unless absolutely necessary, but cable to the mainboard yes.
I had a ASR-X that would power up brown (Lacking power, dim screen, glitchy, barely functional, etc). A good cleaning and she feels like new.
These bad boys can be old!