There's been a few posts about the history of JJP playfield issues. Below is a summary of what I remember occurring over the years. I'm sure this isn't 100% correct as this is just off my memory since WOZ started shipping in 2013. What I learned after reading my comments below...make playfields to the exact spec / process from Hobbit lol.
WOZ
Original run: Some of the early original WOZ ECLE's and SE's with Bader made playfields had severe chipping in the State Fair, pops, and in front of the drop target areas. Part of this issue was due to those areas being high traffic and not having mylar installed from the factory. JJP later sent out mylar kits to customers, customers with chipped areas were offered decals. Again not all WOZ ECLE Bader made playfields were affected. JJP switched to Mirco at some point in either late 2013 or early 2014.
Hobbit
The first JJP game where 100% of the playfields were made by Mirco. From what I've read there's been 0 reports of playfield quality issues with Hobbit playfields. Personally I think the Hobbit playfields are the best playfields JJP has offered (and any manufacturer for that matter) in their games.
Dialed In
Some early Dialed In's had chipping at the SIM card and cell phone scoop. JJP attempted to correct the issue with factory made / installed metal edge protectors. The factory metal edge protectors didn't seem to work well and JJP later switched to installing official Cliffy protectors from the factory at the SIM and cell phone scoops.
Pirates
A majority of Pirates playfield seem affected by pooling / chipping, Pirates also seems to be the first JJP game where pooling is observed. JJP initially didn't install washers under sling posts on early Pirate builds, these games were most affected by pooling / chipping at the sling posts. Sometime in early 2019 JJP started to install plastic washers under sling posts. However, some owners with later build Pirates still reported pooling / chipping at other areas on the playfield.
Wonka
Pooling and chipping with early build Wonka's seemed widespread. Later build games seem to have had the issue corrected but reports of pooling / chipping continued, just not as widespread as with early build Wonkas.
GNR
Similar to Wonka, affecting early build games. Early GNR's didn't appear to be shipped with washers installed under posts, this changed starting sometime in early - mid 2021 with washers being installed under sling posts. Even with factory washers installed at posts some owners have reported pooling / chipping.
Added over 3 years ago:
Updating