[11.3-U3.2] plex plugin jail release update fails

[bal0an]

Yesterday I successully upgraded from 11.2 to 11.3-U3.2. I also upgraded 4 of my 5 jails to release 11.3-RELEASE-p11 using both the Jails | <jailname> | UPDATE feature in the WebUI, and the iocage upgrade --release 11.3-RELEASE <jailname>. All of the updates were successful. Those four jails are not plugin jails.

I have one jail, though, running the plex plugin which is defiant. Using Jails | plex | UPDATE or Plugins | plex | UPDATE ends with

Updating Plugin
Error: [EFAULT] No updates available for plex

when I try iocage upgrade --release 11.3-RELEASE plex I get

root@nas1:/ # iocage upgrade --release 11.3-RELEASE plex
Snapshotting plex...
Snapshot already exists
Updating plugin INDEX...
Traceback (most recent call last):
File "/usr/local/bin/iocage", line 10, in <module>
sys.exit(cli())
File "/usr/local/lib/python3.7/site-packages/click/core.py", line 764, in __call__
return self.main(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/click/core.py", line 717, in main
rv = self.invoke(ctx)
File "/usr/local/lib/python3.7/site-packages/click/core.py", line 1137, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/lib/python3.7/site-packages/click/core.py", line 956, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/lib/python3.7/site-packages/click/core.py", line 555, in invoke
return callback(*args, **kwargs)
File "/usr/local/lib/python3.7/site-packages/iocage_cli/upgrade.py", line 40, in cli
ioc.IOCage(jail=jail, skip_jails=skip_jails).upgrade(release)
File "/usr/local/lib/python3.7/site-packages/iocage_lib/iocage.py", line 2072, in upgrade
).upgrade(jid)
File "/usr/local/lib/python3.7/site-packages/iocage_lib/ioc_plugin.py", line 1308, in upgrade
self.iocroot, 'jails', self.jail, f'{plugin_name}.json'
File "/usr/local/lib/python3.7/shutil.py", line 248, in copy
copyfile(src, dst, follow_symlinks=follow_symlinks)
File "/usr/local/lib/python3.7/shutil.py", line 120, in copyfile
with open(src, 'rb') as fsrc:
FileNotFoundError: [Errno 2] No such file or directory: '/mnt/tank/iocage/.plugins/github_com_freenas_iocage-ix-plugins_git/plex.json'

Is there any workaround?
Of course, I can reinstall plex into a brandnew jail, but I'd like to avoid the hassle of copying or rebuilding the plex database.