Air Conditioner does not act right "some times"

Our front and rear do the exact same thing. I have replaced the electronics and it did not correct the issue. I recently replaced the thermistor style thermostats with digital ones and the problem has gone away. But we have not used them a lot so time will tell. For years we just never set them to auto and just used the high or low setting. I have hopes this is now resolved. I am pretty sure the issue is not with the AC units themselves. Chuck