Resistors do not have any direction. The one that is "reversed" will work fine. Capacitors, transistors and diodes have a direction that are very important.
Sounds like a faulty solder joint. There should have been only two solder joints associated with input one right side. Regardless of how they checked, first measure the resistance from one lead of the "bad" resistor to the other lead. Remember it is probably +/- 10% of the stated value. Then wiggle both ends and see if there is any play. Finally reheat the solder joints and see if it doesn't clear up.