Didn't mean to alarm you more, but rather to put some of your fears to rest.
My point, in suggesting the wood layer on your iSonic 101 is only 0.6 mm (0.0259"... the equivalent of six sheets of 0.004 " computer printer paper) was to inform that the wood layer is very thin, similar in thickness to a layer of fiberglass.
This wood layer is sprayed on both sides with a penetrating type resin, and the moisture content of the wood sheet material is controlled very closely so the wood "soaks" the correct amount of resin as it is applied to your board.
The layer that is under the wood is also completely sealed, so there in never any transfer of moisture beyond the wood layer toward the interior of the board.
Then the board is painted and to get the "fast" finish on the bottom, this paint is very thin and is sanded back some so a tiny bit of grain shows through the paint.
Yes, you could sand all the paint off the wood and resoak the wood with penetrating resin as you suggest, then refinish/fair/paint/finish sand. As you suggest this is quite a task and would require lots of work, and would probably add a bit of weight as well.
What I'm suggesting is to let your board dry, and simply apply the CPEC resin and let it
soak into the wood fibers that are somehow now soaking up water.
Then a quick sanding back to remove any excess CPEC and your boards bottom would now be sealed completely as any wood that can take on water would have pulled in the CPEC resin and thus saturated would not take on anymore water, which would stop the
grain from lifting and curling.
Hope this helps,