Jul 29 11:20:25 Tower kernel: BTRFS info (device nvme0n1p1): bdev /dev/nvme0n1p1 errs: wr 0, rd 0, flush 0, corrupt 609, gen 0
The cache drive has detected corruption and mounted itself as Read only to attempt to protect the system. You should start by running a Memtest from the boot menu for at least a pass or two to eliminate the possibility that memory errors caused this (if you're booting the OS via UEFI, you will need to temporarily switch it to legacy boot in order for Memtest to work)
As an aside, I'm not personally a fan of using BTRFS for a cache pool if you have no intensions of expanding that pool to be a multiple device. XFS is more forgiving on things like unclean shutdowns, memory errors etc.
@JorgeB