The same panel is used on many different boats. I have only one sump and yes it's for the shower. I don't know of 2 sumps on the 310, but your boat is newer than mine. The AC condensate also drains there and that will cause it to cycle. I was surprised at how much moisture comes out of the air in mine.
What is the interval between cycles?
Are you sure it's the sump and not a bilge pump? A bilge pump could be an indicator of failing shaft seal.
It's the diagram on the dash with the outlay of the boat with red indicator indicator lights the one that says forward sump lights for about 10 to 20 seconds then goes out. Does the shower sump trigger that? Also I have I/O's
My best guess is yes. It is the shower sump and the cause of it is AC condensate. The AC if in dehumidify mode will do the same thing.
To test it, run water in the shower drain and see if the light goes on and off. If you listen closely or if you remove the hatch from above the sump for a clearer sound, you will hear it come on in conjunction with the light.