Previous channel button not working

So, we have had our streaming stick for over a year.  The previous channel button worked up until recently when we had to reset the Roku stick (not sure why we had to do that but that's another story).  So, when we reset the stick the volume and channel buttons worked but not the previous channel button.  In order to reset the stick, we were pulling the Roku stick from the TV.  Just out of curiosity we just unplugged the stick from the power source, and it worked.  Can't understand why, but it does work now.