Regardless of single sided guide or dual sided guides on the rear sprocket, that belt is not tracking correctly and needs to be addressed very soon. It looks like it's about 1/4 off the pulley.
In the case of the M3W it can be caused by two things, a twisted rear axle, in this case the right side of the axle would need to be moved forward a bit to bring the belt back onto the rear pulley. If this had dual side guides, the belt would be pushing to the outside guide and would wear the edge of the belt quite badly.
The other possible cause is a bevel box alignment. I'm not sure if that is an option or not, but if you only have two sprockets, it has to be one of them that's out of alignment.
My money would be on the rear wheel needing to be aligned to bring back the belt to the center of the rear sprocket.
Is this type of maintenance listed or shown in the owners manual?
