Interesting,
Not sure what the cause was, but maybe something got in the clutch plate grooves that would not let them move properly, like some debri or something. At this point, barring that your plates are good and not worn out, do a good clean out of everything, reassemble the plates back into the carrier, be very careful to make sure there is no binding in the grooves with nicks on the plates of grooves, put it all back together, set the plate pressure and torque, install, torque everything up, adjust the the clutch rod and cable, with plenty of lube on the cam and ball, cable, and rod. After all that is done, see if everything is right or back to starting point.
I have had plates get jammed before in the carrier due to improper assembly way back in the day.
Hopefully it will all be good and you can get up and ride. Make sure you put loctite on the clutch and engine nuts BTW and torque to proper steps.