When designing the check tray for the restaurant, draft board has proven itself impressively sturdy for the daily abuse it gets. The only exception to the all-around good characteristics is it’s propensity to soak up water. The affected spot bloats up and the once-densely packed wood fibers stay in that loosened state. If this occurs at a glued joint, that area is likely to fail.
The first solution that’d come to mind would be to use polyurethane rather than enamel (spray) paint. I recall trying a spray can of Varathane Spar Urethane and I think it did reasonably well, but it took around 3 days to completely dry to the point the surface would no longer feel tacky. I think this route is still worth pursuing, but maybe with a faster-drying brand.