See picture, count the waves.
Upper track: drums in AFP, 1x oversampling
Lower track: the same with 2x oversampling, sounds an octave too low.

LMMS version: 1.2.0 in Windows 8.1 pro / 64 bit. Didn't find any fitting reported issue, and I think I've used oversampling successfully in the past, so this might be a recent bug.