I have a gray batch 1 (shipped almost the same date as @BigT batch 0). So far don’t see any cracks. Did only open it for the initial build and then another time a few days later. Did screw by feel and not very tight, as I know myself (bad history with overtightening things).
Don’t use it daily, but was travelling for 3+ weeks to literally the other side of the globe. Used it to mostly browse, light work and watching videos. Only around 50% of the days.
Checked yesterday again and don’t see any cracks (yet). IIR the chassis is plastics + aluminium. At least that’s what they said why the laptop is quite heavy for it’s form factor. Wondering if there are sheets of metal in there and cracking is only aesthetics, or if it really could lead to structural problems.
Bottom and top are priced at $49 each. So although unfortunate and hassle to sort out this mess for Framework it might not be as expensive as I initially feared.