Version-Release number of selected component:
dnf-4.8.0-1.fc34

Additional info:
reporter:       libreport-2.15.2
cgroup:         0::/user.slice/user-1000.slice/user/app.slice/app-org.gnome.Terminal.slice/vte-spawn-af45372a-d12d-49f9-b9a8-318c65aaf031.scope
cmdline:        /usr/bin/python3 /usr/bin/dnf history undo 97
crash_function: _revert_transaction
exception_type: KeyError
executable:     /usr/bin/dnf
interpreter:    python3-3.9.6-1.fc34.x86_64
kernel:         5.12.14-300.fc34.x86_64
runlevel:       N 5
type:           Python3
uid:            0

Truncated backtrace:
history.py:233:_revert_transaction:KeyError: 'Reason Change'

Traceback (most recent call last):
  File "/usr/bin/dnf", line 58, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python3.9/site-packages/dnf/cli/main.py", line 201, in user_main
    errcode = main(args)
  File "/usr/lib/python3.9/site-packages/dnf/cli/main.py", line 67, in main
    return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.9/site-packages/dnf/cli/main.py", line 106, in _main
    return cli_run(cli, base)
  File "/usr/lib/python3.9/site-packages/dnf/cli/main.py", line 122, in cli_run
    cli.run()
  File "/usr/lib/python3.9/site-packages/dnf/cli/cli.py", line 1055, in run
    return self.command.run()
  File "/usr/lib/python3.9/site-packages/dnf/cli/commands/history.py", line 342, in run
    self._hcmd_undo(tids)
  File "/usr/lib/python3.9/site-packages/dnf/cli/commands/history.py", line 190, in _hcmd_undo
    self._revert_transaction(old)
  File "/usr/lib/python3.9/site-packages/dnf/cli/commands/history.py", line 233, in _revert_transaction
    ti["action"] = action_map[ti["action"]]
KeyError: 'Reason Change'

Local variables in innermost frame:
self: <dnf.cli.commands.history.HistoryCommand object at 0x7f23e433ea90>
trans: <dnf.db.history.TransactionWrapper object at 0x7f23e4027520>
action_map: {'Install': 'Removed', 'Removed': 'Install', 'Upgrade': 'Downgraded', 'Upgraded': 'Downgrade', 'Downgrade': 'Upgraded', 'Downgraded': 'Upgrade', 'Reinstalled': 'Reinstall', 'Reinstall': 'Reinstalled', 'Obsoleted': 'Install', 'Obsolete': 'Obsoleted'}
data: {'version': '0.0', 'rpms': [{'action': 'Removed', 'nevra': 'kernel-5.13.1-300.fc34.x86_64', 'reason': 'unknown', 'repo_id': '@commandline'}, {'action': 'Removed', 'nevra': 'kernel-core-5.13.1-300.fc34.x86_64', 'reason': 'unknown', 'repo_id': '@commandline'}, {'action': 'Removed', 'nevra': 'kernel-modules-5.13.1-300.fc34.x86_64', 'reason': 'unknown', 'repo_id': '@commandline'}, {'action': 'Removed', 'nevra': 'kernel-modules-extra-5.13.1-300.fc34.x86_64', 'reason': 'unknown', 'repo_id': '@commandline'}, {'action': 'Reason Change', 'nevra': '1password-8.1.1-1.x86_64', 'reason': 'user', 'repo_id': '1password'}, {'action': 'Removed', 'nevra': 'kernel-5.12.9-300.fc34.x86_64', 'reason': 'user', 'repo_id': '@System'}, {'action': 'Removed', 'nevra': 'kernel-core-5.12.9-300.fc34.x86_64', 'reason': 'user', 'repo_id': '@System'}, {'action': 'Removed', 'nevra': 'kernel-modules-5.12.9-300.fc34.x86_64', 'reason': 'user', 'repo_id': '@System'}, {'action': 'Removed', 'nevra': 'kernel-modules-extra-5.12.9-300.fc34.x86_64', 'reason': 'user', 'repo_id': '@System'}]}
content_type: 'rpms'
ti: {'action': 'Reason Change', 'nevra': '1password-8.1.1-1.x86_64', 'reason': 'user', 'repo_id': '1password'}

Potential duplicate: bug 1966550