Run solenoid test. Make sure each coil fires only one at a time and make sure they fire in the order shown in the manual. If any fire out of order or more than one fires at a time, rebuild the female connector J4 on both CPU and SDB boards.
If all fire in order one at a time, you likely have a switch matrix issue. Remove ball and test every switch in the columns and rows affected. Make sure correct switch shows on display and no single switch triggers more than one switch. All test good? Put a ball in the saucer and test the switches again. Sometimes it takes another switch to be closed for the symptom to show. Lastly, check the gap on the flipper EOS switches. Early Bally's can act up with gap too small.