Software and Updates broken in Ubuntu MATE 24.04

[Brian Bogdan]

I am unsure when this actually happened but Software & Updates has stopped working. Here is the error when launching it from Terminal:

xWarning: invalid escape sequence '\.'
  elif re.match("^((ftp)|(http)|(file)|(rsync)|(https))://([a-z]|[A-Z]|[0-9]|:|/|\.|~)+$", uri) == None:
Traceback (most recent call last):
  File "/usr/bin/software-properties-gtk", line 100, in <module>
    app = SoftwarePropertiesGtk(datadir=options.data_dir, options=options, file=file)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 163, in __init__
    SoftwareProperties.__init__(self, options=options, datadir=datadir,
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 109, in __init__
    self.backup_sourceslist()
  File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 437, in backup_sourceslist
    source_bkp = SourceEntry(line=source.line,file=source.file)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/aptsources/sourceslist.py", line 509, in __init__
    raise ValueError("Classic SourceEntry cannot be written to .sources file")
ValueError: Classic SourceEntry cannot be written to .sources file

I have tried reinstalling the application but I cannot get it to work.

Ubuntu MATE 24.04
kernel 6.8.0-11

[Brian Bogdan (bbogdan-i)]

added file from /var/crash