MariaDB service fails to start with InnoDB Space id error - mysql

Question

I've been running MariaDB on a Raspberry Pi 4 (Raspbian 10 / buster) as the database server for my Webtrees and Owncloud sites. Recently, I noticed that the server wasn't looking right, and after a reboot, I can see that the MariaDB service is failing to start.
Contents of /var/log/mysql/error.log:
2021-03-26 14:45:06 0 [Note] InnoDB: Using Linux native AIO
2021-03-26 14:45:06 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2021-03-26 14:45:06 0 [Note] InnoDB: Uses event mutexes
2021-03-26 14:45:06 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2021-03-26 14:45:06 0 [Note] InnoDB: Number of pools: 1
2021-03-26 14:45:06 0 [Note] InnoDB: Using generic crc32 instructions
2021-03-26 14:45:06 0 [Note] InnoDB: Disabling background log and ibuf IO write threads.
2021-03-26 14:45:06 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2021-03-26 14:45:06 0 [Note] InnoDB: Completed initialization of buffer pool
2021-03-26 14:45:06 0 [Note] InnoDB: innodb_force_recovery=6 skips redo log apply
2021-03-26 14:45:06 0 [ERROR] InnoDB: Space id and page no stored in the page, read in are [page id: space=0, page number=399], should be [page id: space=0, page number=394]
210326 14:45:06 [ERROR] mysqld got signal 11 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
To report this bug, see https://mariadb.com/kb/en/reporting-bugs
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.
Server version: 10.3.27-MariaDB-0+deb10u1
key_buffer_size=134217728
read_buffer_size=131072
max_used_connections=0
max_threads=153
thread_count=0
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 466214 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.
Thread pointer: 0x0
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 0x0 thread_stack 0x49000
The manual page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mysqld/ contains
information that should help you find out what is causing the crash.
Writing a core file...
Working directory at /var/lib/mysql
Resource Limits:
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 12860 12860 processes
Max open files 16384 16384 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 12860 12860 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us
Core pattern: core
Here's the terminal output from trying to start fro the terminal:
$ sudo systemctl restart mariadb.service
Job for mariadb.service failed because the control process exited with error code.
See "systemctl status mariadb.service" and "journalctl -xe" for details.
Googling hasn't turned up too much, though I've tried
innodb_force_recovery = 1
innodb_purge_threads=0
In /etc/my.cnf, which didn't seem to change anything.
Any thoughts before I attempt to restore from backup?