That isn't a good sign, in general this means the controller sustained some water damage. It can also be due to a signal conflict, i.e. float is raised and optic sensor registers a too low water level. If the controller is mounted in a known dry place, the water damage is less likely, if it was mounted near something that may have spilled or overflowed or left sitting on the floor of a stand, this is very likely the issue. If you can tell me more about the set up or post a picture we may be able to troubleshoot it further, you might also open the controller and look for any water damage, it just takes one drop getting to the board.