raise your playfield & un-plug your recently replaced optos (4pin plug orange/black/grey wires), start a game and wait to see what happens, if nothing happens or if diverter flips once or twice and then stops completely you do indeed have an opto problem - plug it back in and start another game just to make sure problem returns.
if diverter continues to actuate with the optos un-plugged you probably are having a driver board related issue and needs much more investigation
like some one above mentioned, test the opto voltages on the rear of the optos, should be 12-13volts on each, if one is low (1-3 volts) you may have the new opto soldered in backwards - they only work in one direction, this doesn't sound like your problem since yours works in test mode
the receiver (black) opto at this location is very sensitive to having the emiter lined up correctly and sometimes takes a bit of bending / tweaking of the mounting locations on the ramp to get perfectly aligned, if not aligned correctly you will indeed get multiple signals from your optos
finally make sure opto mounting screws are snug once you sort out your problem
hope this helps ....