Marker light with photo cell on the blink!

[L124C]

One of the channel marker lights in my marina is coming on during the day, and turning off at night! The marina staff has made several attempts to fix it but obviously doesn't know what to do. With my limited electrical knowledge, I'm thinking: The light works, the photo cell apparently works, knowing night from day. However, somewhere things are getting confused. Any ideas before I go out there and look at it? I can take a picture of the unit if it will help.
If you are wondering why I would bother, I did another thread on the deterioration of what was a very nice marina (several lights didn't work at all for 6 months). Don't get me started again!