This is a true Fontainebleau mantle. You have to mantle on your heelhook that will only work when it’s placed perfectly. Twisting the hands to mantle up is tricky which makes it extra rewarding when you manage to mantle up!
Rain sucks, but broken holds suck even more. Remember, never climb on wet rock in Fontainebleau.
The sandstone becomes brittle, and pulling on it will ruin classic problems. Drying it doesn't help, because it's still wet and weak inside.
All you can do is wait for better conditions.