Been poking around in the machine (looovely) ran across this bug.
1: KarmaFX 2.0 Build 279 Demo 32 bit
2: Synapse Audio Orion Studio 8.612
3: Bug: Sampler loops FORWARD between markers but when switched to BACKWARDS it loops outside (before) start marker.
4: Reproduced with several samples and several instances of KarmaFX Modular