Unable to copy large amounts of data to new btrfs partition

On Armbian Buster, rockchip (rock64), kernel 5.16.69. This was also happening on the latest backported version of 5.10, I think 5.10.72? I tried upgrading to fix it to no avail.

I have a couple 8TB HDDs that I use as backups. All I did was reformat one of them as btrfs and start copying the data back over from the other (still EXT4). I tried rsync and simple cp. Without fail, a few minutes into the operation, the copy operation will hang indefinitely, and all open terminals receive these kernel messages:
 

Message from syslogd@localhost at Oct 1 16:59:57 ...
 kernel:[ 339.539365] Internal error: Oops: 96000004 [#1] PREEMPT SMP
Message from syslogd@localhost at Oct 1 16:59:57 ...
 kernel:[ 339.560387] Code: cb0100a3 cb0d015c 7100019f 9b167c00 (9adb2400)

After that, every subsequent copy operation from the EXT4 drive to this new btrfs partition will hang until I reboot the rock64.

However, the drive otherwise continues to work fine. fsck and btrfs scrub find no problems. The super weird thing is I can still write files, and copy a small shell script from the home folder, all just fine--but copying from the other 8TB drive will immediately hang. I have had zero issues with either drive until trying btrfs now. I'm able to rsync between them just fine when they're both EXT4.

journalctl.txt specific-error.txt