That's a fairly typical design that works well 99% of the time for letting cars turn right and bikes go through the intersection. Lots of cities have similar arrangements.
I would call or email the bus company and let them know what happened. They can probably figure out which bus/driver from the location and time/date.
https://mbtabus.com/ <-- is this the bus company? There's a phone and email at the bottom of the page.