I have an 89 camry and had the same problem with my indicator. Sometimes if I hit a bump just right one of the bulbs would turn off or on, it was really annoying. I was sure that it had to be a bad bulb or bad connection with the bulb. However, when I tore it all apart I discovered that the bulbs were good. It was actually bad solder connections where the connection goes straight through the circuit board to the other side. The connection looks like a little dot, where a trace ends, and continues through the circuit board to the flip-side of the circuit board, to continue to its destination. I discovered this when I was probing the circuit board with my test probe, when I touched one of these connections the bulb would light up and go out again when I stopped touching it. I also had a similair problem with the rear brake lights. All of the brake lights stopped working, the brake switch was good, and the "lights" indicator on the dash came on when I stepped on the brake to let me know I had a bulb out. I didn't realize that they had all stopped working until I decided to go change the burned bulb, I was driving around like that for about 2 weeks! I discovered that the problem was with the light failure sensor that is mounted in a little plastic box, drivers side in the trunk behind the covering. There were solder connections at the plug that had broke loose, this was easily fixed by reheating the solder to recreate the connection. I know another person that had the exact same problem with this on their camry.
So basically either you have another faulty indicator, or perhaps its a problem down at the shifter, or wherever it is that selects which bulbs to light up. Obviously you have power going to the indicator if some of the bulbs light up. Easiest thing to do is to check and make sure you have power coming out of the harness connector for each gear, the O/D switch, and pwr switch. If its good there then its the indicator. If you have a soldering iron you can repair it yourself.