Not necessarily. Something has to give way first. If the ink, regardless of whether it’s printed or silkscreened, sticks less to the wood than it does the clear, it’s going to lift up with the clear. It doesn’t mean you used the wrong ink or the wrong process of applying it.
I don’t profess to know anything about manufacturing a playfield, but I’m more inclined to believe that the real issue is with the clear. I shouldn’t be able to make a mark in the playfield with my finger nail. Period.
Really, artwork coming off the wood with the bubbling clear is no more surprising to me than being able to use a piece of silly putty to lift some of the ink up off of a Sunday comic strip in the newspaper. In this case, the ink’s adhesion to the clear is strong enough that, in some cases, all of it, rather than part, is coming up. And, depending on the properties of the wood, it shouldn’t be too surprising to see some of it splintering off with the clear as well. The path of least resistance is always going to win.
I don’t think removing the artwork from parts of the playfield solves anything... other than the manufacturer hoping bubbling and chipping clear might be less noticeable to the buyer when it’s happening over plain wood versus seeing it over artwork and having parts of that artwork coming up off of the playfield.