Quoted from D-Gottlieb:My thinking is that problem lies in the wood of the playfield. The wood expands, contracts and the insert effectively sinks. If the wood were completely cured/dry, the ghosting would not occur.
I used to make furniture, still have all my equipment, and have some experience with finishing. I don't know exactly what the issue is but it may very well have to do with cure time. Whatever products they are using are not being allowed to cure before moving to the next step or are not curing in the right conditions (too much or too little humidity, for example).
It could also be a chemical reaction between products, especially if something changed. For example, they may be wiping/sanding between coats with something causing issues. The tiniest bit of silicone will kill adhesion. If you wax your table saw and that wax has silicon in it, kiss your wood goodbye.
Environmental issues may also be having an impact as more and more chemicals get watered down. Or Stern and/or its finisher cut back to save a few dollars.
What's interesting, however, is why JJP doesn't seem to have these issues. Presumably, the same or very similar products are being used, which leads me back to cure time or a change in their products and /or process.
If I buy a piece of furniture and it started to haze, crack, ghost, whatever, it would be going back to the store. Stern's policy is not very good and it's just not normal. Dimples, yes.
I keep my games in a temp controlled environment with temp around 70 and RH at 50% and thankfully haven't had issues so far.