long samples stopping during playback!

I've had this issue, and found that if I'm using a ride cymbal or open Hi Hats in my beat, some long guitar or bass guitar samples would stop playing half way through the bar, even though the whole guitar/bass samples are all there. Try changing the open Hi Hats or Ride cymbal if you're using either in your beat, to a closed Hi Hat. This worked for me. It's a strange quirk this machine has. I can only assume it struggles with too many long samples, as the bass, and first guitar samples played fine, but when I added another long guitar sample, then it started to happen. If you have any info about this, that I'm not aware of, I'd be only too pleased to know how you solved the problem you had.

Which operating system are you using?

The MPC 2500 has 32 voices of polyphony, meaning at any one time you can either have 32 mono samples triggering at the same time or 16 stereo samples.

This is plenty of polyphony for beat making but if you have a very busy arrangement it's possible to experience voice stealing.

Are you sure you aren't just experiencing voice stealing? I have never heard of this bug you describe and the MPC2500 has been around for over 20 years. It would be much more widely known if it truly existed.

An easy way for you to test if the bug you describe is actually what you think it is, is by creating a new program / sequence and recording a long sample. Place that sample on the first beat and see if it still cuts off. If it doesn't cut off it's because you are experiencing voice stealing or are specifically using pad mutes to mute the sample