Apparently the latest is that lots of people around the world are having issues with GB and SMVE with cracking around inserts, inserts dropping & rising, crazing and insert ghosting (similar to MMr) so who ever is making their playfields are getting worst. I to a local who has a GB Pro who said his mate who has a GBLE has ghosting, cracking around his inserts and a few inserts have dropped down lower than the playfield.

All starting to point to unseasoned timber. Appears to be very soft when you get a game hence the dimples which flatten out ( timber seasoning itself) and then shrinking also ( cracking or coming away from inserts).
It does very much sound like "green" ply being used to me.