A bit puzzled

So I haven't had any difficulty with my mpc (1k, free jjos) for months, and all of a sudden the most random issue comes up.

I've got a sample that I'm trying to put some LFO on, a saw LFO on the level of the sample, to sound kinda like ducking/compressor but not really.

But I can't actually get it to do anything.
I can get the expected level LFO modulation on any of the other waveforms. I can also get the saw LFO modulating pitch or filter correctly. I've tried lowering the original volume of the sample, since the saw LFO adds to whatever value it's modulating, unlike the saw down which subtracts. But nothing happens.

I'm puzzled, anyone have this issue/have an idea of what the problem is?

maybe you have a short sample or some attack so wave happens too quick for LFO to act on it. Thats what i think when i read your post.

It's a long sample, like 16 beats, so that's not the problem.

I forgot to mention originally, I had Full Level turned on at the time. Turning it off and not hitting with full velocity made the LFO work correctly.

So clearly that's related to the issue, but why would only the Saw waveform LFO not work? All of the other shapes worked fine with Full level on, and the Saw shape worked with anything other than Level modulation.

you can only get this behavior when using this one sample?

try creating a new program. do it from there. same thing?