I have a Hampton Bay Flow fan w/light kit and built in remote. It worked fine for a week, then started behaving erratically. Fan speed would change on its own. Light would turn on and/or off on its own. I figured it was the dip switches, but now the light only works when I turn the wall switch on in the morning first thing, then after a while the light stops working. If I turn on the wall switch and leave the light and fan on, eventually the light goes out, and will not turn on till I leave the wall switch off for several hours.

Best guess is there is another wireless remote operating something else, like a neighbors fan, and you are both on the same frequency. There is a series of dip switches in the receiver in the canopy. Another set a dip switches are in the remote under the battery cover. Basically they are a series of I / O so just move all switches on both units to O

Please read this article about ceiling fan remote troubleshooting.

It has a part about dip switches, like the above gentleman is talking about.

You will need to change the dip switch pattern to something different, in order to change the "frequency" that the fan operates on. You'll need to ensure the new pattern is the same on both the fan and the remote as well.