Hello,
same boat, same problem. I did not notice any tiny holes actually but I will check better. I've installed a unidirectional valve on the sump pump line because my opinion was that the water is filling in during turns from the right hull fittings.. but the water still fills.
I do not understand the problem.. I have 4 thru-hull fittings on the right side of the boat for sink, shower sump, middle sump pump and other 2 unknown (may be A/C if installed) and I clearly hear gurgle noises during right roll turns. I have to solve..