Continuity L-N won't trip the RCD. It will make a loud bang, spit out some molten metal, leave a burn mark and trip the MCB.
Anyway, let's suppose there's 'moisture' causing leakage L-E. We need to be clear what that 'moisture' is. A bit of condensation on the surface of a terminal block will not trip an RCD, it needs to be properly wet. What is the highest insulation resistance that can possibly trip an RCD? A typical RCD trips around 22mA, let's suppose there's 4mA of leakage already on it and it only needs 18mA from the insulation breakdown. That would put the insulation at 230 / 0.018 = 12.8kΩ. Considering that most circuits achieve 10,000 times better insulation or more, gives an idea of why that's spectacularly low.
0.018 * 230 = 4W of heat dissipated at the fault. That is enough heat to melt insulation and cause rapid corrosion. Then there is the subject of surface tracking. When significant leakage takes place through water over a period of time, metal ions are dissolved from the conductors and can be deposited on the surface of the insulation. This is very much more serious on DC but it does still occur on AC. When the moisture evaporates, a surface track of degraded insulation strength is left behind. If the problem is at terminals they are likely to be badly corroded and high-resistance. The last 'damp' fitting I saw that had just occasionally started tripping an RCD was a double-socket with free water in the back box that ran down the wall when I drew a Stanley knife round it to break the paint seal. It was so badly corroded that the terminal screw heads had rusted away and the conductors were jet black with copper oxide for 3cm inside the insulation.
It's often OK to dry out moisture if it's fresh and / or the parts have not yet been subjected to mains voltage. But it is not safe simply to dry things out when they have likely been simultaneously subjected to moisture and voltage for an unknown period.