cross-platform backup tool Traceback of failed backup

Can someone please make sense of this traceback from a rdiff-backup 2.0.5 client backing up to a rdiff-backup 2.1.3b3 server.

The directory /usr/lib/modules/5.19.12-200.fc36.x86_64/extra is deleted since the previous backup. The entire /usr/lib/modules/5.19.12-200.fc36.x86_64 subtree was deleted by the most recent kernel update. It exists and verifies OK in the previous backup.

Warning: Local version 2.0.5 does not match remote version 2.1.3b3.
Exception 'Either diff '<RORPath/140364064494144:
	Index=('usr', 'lib', 'modules', '5.19.12-200.fc36.x86_64', 'extra')
	Data={'type': None, 'filetype': 'snapshot'}>' or base '<RPath/140364064904528:
	Path=/media/sysbk/lenovo-F36/usr/lib/modules/5.19.12-200.fc36.x86_64/extra
	Index=('usr', 'lib', 'modules', '5.19.12-200.fc36.x86_64', 'extra')
	Connection=LocalConnection
	Data={'type': None}>' must be a directory' raised of class '<class 'AssertionError'>':
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 395, in error_check_Main
     Main(arglist)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 417, in Main
     take_action(rps)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 353, in take_action
     Backup(rps[0], rps[1])
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 439, in Backup
     backup.Mirror_and_increment(rpin, rpout, incdir)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/backup.py", line 55, in Mirror_and_increment
     DestS.patch_and_increment(dest_rpath, source_diffiter, inc_rpath)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/connection.py", line 526, in __call__
     return self.connection.reval(*(self.name, ) + args)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/connection.py", line 439, in reval
     raise result

Traceback (most recent call last):
   File "/usr/bin/rdiff-backup", line 32, in <module>
     rdiff_backup.Main.error_check_Main(sys.argv[1:])
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 395, in error_check_Main
     Main(arglist)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 417, in Main
     take_action(rps)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 353, in take_action
     Backup(rps[0], rps[1])
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/Main.py", line 439, in Backup
     backup.Mirror_and_increment(rpin, rpout, incdir)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/backup.py", line 55, in Mirror_and_increment
     DestS.patch_and_increment(dest_rpath, source_diffiter, inc_rpath)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/connection.py", line 526, in __call__
     return self.connection.reval(*(self.name, ) + args)
   File "/usr/lib64/python3.10/site-packages/rdiff_backup/connection.py", line 439, in reval
     raise result
AssertionError: Either diff '<RORPath/140364064494144:
	Index=('usr', 'lib', 'modules', '5.19.12-200.fc36.x86_64', 'extra')
	Data={'type': None, 'filetype': 'snapshot'}>' or base '<RPath/140364064904528:
	Path=/media/sysbk/lenovo-F36/usr/lib/modules/5.19.12-200.fc36.x86_64/extra
	Index=('usr', 'lib', 'modules', '5.19.12-200.fc36.x86_64', 'extra')
	Connection=LocalConnection
	Data={'type': None}>' must be a directory
WARNING: this command line interface is deprecated and will disappear, start using the new one as described with '--new --help'.
NOTE: Extended attributes not supported by filesystem at path /media/sysbk/lenovo-F36/rdiff-backup-data/rdiff-backup.tmp.0 due to exception '[Errno 95] Operation not supported'
Traceback (most recent call last):
   File "/usr/bin/rdiff-backup", line 11, in <module>
     load_entry_point('rdiff-backup==2.1.3b3', 'console_scripts', 'rdiff-backup')()
   File "/usr/lib64/python3.6/site-packages/rdiffbackup/run.py", line 37, in main
     sys.exit(main_run(sys.argv[1:]))
   File "/usr/lib64/python3.6/site-packages/rdiffbackup/run.py", line 105, in main_run
     ret_val |= conn_act.run()
   File "/usr/lib64/python3.6/site-packages/rdiffbackup/actions/server.py", line 66, in run
     sys.stdout.buffer).Server()
   File "/usr/lib64/python3.6/site-packages/rdiff_backup/connection.py", line 404, in Server
     self._get_response(-1)
   File "/usr/lib64/python3.6/site-packages/rdiff_backup/connection.py", line 448, in _get_response
     req_num, object = self._get()
   File "/usr/lib64/python3.6/site-packages/rdiff_backup/connection.py", line 298, in _get
     hdr=header_string))
rdiff_backup.connection.ConnectionReadError: Truncated header <b''> (problem probably originated remotely)

-- 
Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.