It is not "normal" but it may not be uncommon. There are necessarily gaps between the liner and the hull throughout the boat so the source could be anywhere "up stream" from the given location. First determine whether the water is salt
or fresh and then check the usual suspects although it could also be from an unusual source.
While it may not be particularly helpful, for what it's worth, places that I have found elusive leaks
over the years (but on several different boats) include a crack in an exhaust
hose in the riser above the thru-hull; a crack in the mixing elbow
on our 4-108 when it was at roughly 3100 hours; a worn lip seal in a Johnson raw water-pump that allowed water to enter the bearing chamber and then escape; a broken drain-plug in the body of a Groco raw water
strainer; a failing pressure relief valve in a water heater that only leaked when it was hot; a leak from corrosion
in the welds on a stainless-steel water-lift muffler
; an intermittent leak around the edges of the pulse damper on the underside of a pressure water pump; a leak at the cuff of a fresh-water fill hose at one of our water tanks
when a very hard to reach, to say nothing of see, hose clamp failed; a crack in the spout of a sink-drain in one of our heads (the drain hose was bent at a sharp angle applying a bending load to the spout which failed as it aged). This litany could go on but the foregoing were some of the more problematic.