The carbon fibre floats may be porus allowing water to seep in at depth.
Even a minute pore could allow a drop per minute.
In industrial applications a 'quick & dirty' solution is called 'impregnation'. (google "casting impregantion ...".
If the leak is very small, spraying the outside of the float with clear coat could stop the leak, providing it is not a mechanical one in the closure joints.
Additionally, if it is porosity then: they may be more that one, and it is a basic manufacturing defect. If the later, then Nauticam seems to be a reputable company and they should resolve the problem.