When I removed my sink and faucet during a recent countertop replacement, I found a cracked fitting. I do not have hot water in my van, so SMB closed off the hot water supply line with a CPVC cap on the nylon supply line adapter. The CPVC cap had major though-cracks. If the hot water tap stays turned off, that will prevent the cold from back-feeding into the hot side of the faucet but things can get bumped. No signs of leaks but I replaced it with a galvanized cap.
CPVC cap with nylon adapter still installed. Cracks run the length of the fabbed cap:
End view of cap with the adapter removed and sitting beside it. Note through crack at top of cap:
This is the installed location before the sink was put into the new counter. Cold feeds in from right and up to faucet. Galvanized cap and nylon adapter are to the left of the cold:
(The grey furry box with the black tubes is my grey water tank which is in the cabinet.)
If you have a cold water only rig, this would be worth checking.