So I ran into this bug yesterday and after 2 hours of trying to fix it, it really drove me bonkers.
I have downloaded the Gold Baby - Blofeld Drums free sample pack and the bassdrums seem to have either meta-tags, or Machine is trying to be smart with it. (I am using the samples pure, not via a mixgrp or anything. - https://www.goldbaby.co.nz/freestuff.html)
The problem is that loading 'some' samples just erases (or doesn't set the full sample zone and the volume gets zet to zero! In prehear it is audible, but once loaded to a pad, zone and volume are messed up!
Additional, other samples like claves, hihats and such from the same pack, don't mess with the zone and volume and work like they should.
Anyone know how to fix it? I'm not going to re-set these anytime I use the sample.
I found earlier posts who encountered the same problem, even mentioning it being solved, well.. not quite yet!
https://www.native-instruments.com/forum/threads/sounds-preview-but-dont-play.344147/
https://www.native-instruments.com/forum/threads/maschine-2-0-problems-loading-samples.213363/#post-1336442