I picked up a nice 4-switch Telegames over the weekend, and ran into an odd issue that I haven't seen when using the Harmony with other models. Often, when turning on the system, it will think paddles are connected, even though I'm just using a plain old Wico Ergostick. If I hold down the joystick button while powering on (like when this same thing happens with Genesis controllers), it works perfectly fine, and I can load and play games with no issues.
When I got the console, I had to fix a loose solder joint on the left joystick port. Might there be other bad joints, or unintentionally bridged pins that would be making the Harmony think I have paddles connected?