An update... I encountered blinking LEDs while I was away from my
computer again.
I'm now pretty confident it wasn't an issue with btrfs balance, but
rather the sd-card not being seated well.

I just updated my old "F2FS Segmentation fault" post in linux-f2fs-devel.
In short, fsck for f2fs was failing, badblocks was coming up with only
errors, I cleaned the sd-card contacts, put it back in and badblocks
is running cleanly now.
It's just too late for me, and I have to rebuild that partition since,
for whatever reason, cryptsetup no longer recognizes the partition as
being LUKS even though badblocks was run non-destructive.

On Fri, Mar 26, 2021 at 11:51 AM Nathan Royce [off-list ref] wrote:

Oh man, I'm hoping things aren't starting to fall apart here.
I was doing my normal routine (tv, browsing, ... (no filesystem
manipulations)) and out of the blue "kodi" just crashes. It's actually
not all that uncommon, and I fired up "iotop" to make sure "coredump"
was happening, and it was.
I then did something else in the terminal, maybe an "ls", and that came up with:
*****
error while loading shared libraries: /usr/lib/libutil.so.1: ELF file
version does not match current one
*****

...