**Steps to reproduce**
```
$ python pwb.py cfd -lang:en -family:wikipedia -simulate
Robot - Speedily moving category Academics by university in Zimbabwe to [[:Category:Faculty by university in Zimbabwe]] per [[WP:CFDS|CFDS]].
WARNING: The category page target 'Category:Faculty by university in Zimbabwe' already exists.
WARNING: The category talk page target 'Category talk:Faculty by university in Zimbabwe' already exists.
Robot - Speedily moving category Academics by university or college in Uganda to [[:Category:Faculty by university or college in Uganda]] per [[WP:CFDS|CFDS]].
...
WARNING: The category page target 'Category:Kwame Nkrumah University of Science and Technology faculty' already exists.
WARNING: The category talk page target 'Category talk:Kwame Nkrumah University of Science and Technology faculty' already exists.
SIMULATION: wbeditentity action blocked
Traceback (most recent call last):
File "pwb.py", line 250, in <module>
if not main():
File "pwb.py", line 243, in main
run_python_file(filename, [filename] + args, argvu, file_package)
File "pwb.py", line 95, in run_python_file
main_mod.__dict__)
File "./scripts/cfd.py", line 237, in <module>
main()
File "./scripts/cfd.py", line 195, in main
robot.run()
File "/home/pavel/pywikibot/scripts/category.py", line 695, in run
self._update_wikibase_item()
File "/home/pavel/pywikibot/scripts/category.py", line 842, in _update_wikibase_item
item.setSitelink(self.newcat, summary=comment)
File "/home/pavel/pywikibot/pywikibot/page.py", line 4595, in setSitelink
self.setSitelinks([sitelink], **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 4636, in setSitelinks
self.editEntity(data, **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 128, in wrapper
handle(func, self, *args, **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 107, in handle
func(self, *args, **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 4230, in editEntity
self.latest_revision_id = updates['entity']['lastrevid']
KeyError: 'entity'
CRITICAL: Exiting due to uncaught exception <class 'KeyError'>
```
```
$ python pwb.py cfd -lang:en -family:wikipedia
Robot - Speedily moving category Academics by university in Zimbabwe to [[:Category:Faculty by university in Zimbabwe]] per [[WP:CFDS|CFDS]].
WARNING: The category page target 'Category:Faculty by university in Zimbabwe' already exists.
WARNING: The category talk page target 'Category talk:Faculty by university in Zimbabwe' already exists.
Robot - Speedily moving category Academics by university or college in Uganda to [[:Category:Faculty by university or college in Uganda]] per [[WP:CFDS|CFDS]].
...
WARNING: The category page target 'Category:Kwame Nkrumah University of Science and Technology faculty' already exists.
WARNING: The category talk page target 'Category talk:Kwame Nkrumah University of Science and Technology faculty' already exists.
WARNING: API error failed-save: The save has failed.
Traceback (most recent call last):
File "/home/pavel/pywikibot/pywikibot/page.py", line 107, in handle
func(self, *args, **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 4229, in editEntity
baserevid=baserevid, **kwargs)
File "/home/pavel/pywikibot/pywikibot/tools/__init__.py", line 1738, in wrapper
return obj(*__args, **__kw)
File "/home/pavel/pywikibot/pywikibot/site.py", line 1320, in callee
return fn(self, *args, **kwargs)
File "/home/pavel/pywikibot/pywikibot/site.py", line 7856, in editEntity
data = req.submit()
File "/home/pavel/pywikibot/pywikibot/data/api.py", line 2079, in submit
raise APIError(**result['error'])
pywikibot.data.api.APIError: failed-save: The save has failed. [help:See https://www.wikidata.org/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce> for notice of API deprecations and breaking changes.]
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "pwb.py", line 250, in <module>
if not main():
File "pwb.py", line 243, in main
run_python_file(filename, [filename] + args, argvu, file_package)
File "pwb.py", line 95, in run_python_file
main_mod.__dict__)
File "./scripts/cfd.py", line 237, in <module>
main()
File "./scripts/cfd.py", line 195, in main
robot.run()
File "/home/pavel/pywikibot/scripts/category.py", line 695, in run
self._update_wikibase_item()
File "/home/pavel/pywikibot/scripts/category.py", line 842, in _update_wikibase_item
item.setSitelink(self.newcat, summary=comment)
File "/home/pavel/pywikibot/pywikibot/page.py", line 4595, in setSitelink
self.setSitelinks([sitelink], **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 4636, in setSitelinks
self.editEntity(data, **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 128, in wrapper
handle(func, self, *args, **kwargs)
File "/home/pavel/pywikibot/pywikibot/page.py", line 120, in handle
raise pywikibot.OtherPageSaveError(self, err)
pywikibot.exceptions.OtherPageSaveError: Edit to page [[wikidata:Q8219034]] failed:
failed-save: The save has failed. [help:See https://www.wikidata.org/w/api.php for API usage. Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce> for notice of API deprecations and breaking changes.]
CRITICAL: Exiting due to uncaught exception <class 'pywikibot.exceptions.OtherPageSaveError'>
```