"check whether your Saramonic has Mic Level Output or just Line Level Output" I really don't know, what I know is the smartrig+ work fine with my Nikon d5500, and none of the preamp I've tried work with the XT-3. I'm just receiving a pulse signal.
When I plug headphones in the saramonics smartrig+, I constantly heard this pulse, like the microphone is on and off at a regular rythme, so it's not contact failure.
I'm quite sure the issue come from the camera, I've heard other people experiencing this issue with the X-T3.