Hoping to get some advice. I returned a used F40 traditional and exchanged for a "new" F40 Traditional. When the guitar arrived, it looked dried out and the action was very low. I shimmed the saddle, but the guitar is now in 50% humidity and I notice the action keeps rising, and I see some bellying of the top, especially on the bass side. If I put straight edge across the top behind the bridge, the gap at the bass edge is close to 1/4". I don't see any bracing issues... Not sure if this would be considered normal. WOuld this be concerning to you? Any advice on what I should do? Thanks!