I spent some time with the developper trying your samples.
When you play a sample, it will be stretched to fit the app's BPM.
Your samples have different BPMs from one another.
When you play a lot of samples that have different BPMs, they will all be stretched, which may be demanding for your device, and that will cause performance issues, hence the distorsion you are hearing. As RoJeC points out, this is probably CPU stress load.
The main thing we can advise you is to have samples that have the same BPM (or modify your samples so they have the same BPM).
Are all your samples meant to be played together ?
A few other precisions :
This is problem is not linked to the RAM.
The sample rate doesn't have a role either, the app resamples all your loops when they are loaded.
We would also generally advise to turn the HQ limiter on.
Hope this information helps,