I would guess because of this (presumably this has happened more than once)
Dec 25 20:12:34 fallout emhttpd: unclean shutdown detected
You've now got some cache pool problems
Dec 25 20:14:23 fallout kernel: BTRFS info (device sdo1): bdev /dev/sdo1 errs: wr 20410, rd 13244, flush 4, corrupt 0, gen 0
Dec 25 20:14:23 fallout kernel: BTRFS info (device sdo1): bdev /dev/sdp1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0
Dec 25 20:14:23 fallout kernel: BTRFS info (device sdo1): bdev /dev/nvme0n1p1 errs: wr 0, rd 17, flush 0, corrupt 0, gen 0