I'm also having this problem, not using CKAN though. It only seems to happen on the stock and KSPIE retractable solar panels and the SP-G Shrouded Solar Array from the Mk2 Expansion mod; all other solar panels work fine. I didn't edit the non-retractable panels to be retractable so I didn't test every solar panel, but I did test every retractable panel from stock, near future solar, KSPIE and the single panel from Mk2 Expansion. I tested with my normal 100+ mod list and with just KSPIE + Near Future Solar.
It seems that when you close the panels it subtracts the energy that the solar panel would make in stock KSP. So the panel is making 1.61 EC/s (0.00161 MW) when open, but when it's closed you lose the energy it would make with the stock system (1.37 EC/s). If the panel was not making energy due to being blocked by something you don't lose the energy. You can reopen the solar panel, it will stop using energy and produce the correct amount of power. So I'm guessing the problem is it's supposed to stop subtracting the stock power when closed but doesn't.