Looks like it is the same as T192912

Due to

if code == 'failed-save' and \
   self.action == 'wbeditentity' and \
   self._is_wikibase_error_retryable(result['error']):
    self.wait()
    continue

it seems that action is not 'wbeditentity'; any idea what it was?

See also rPWBC5d636a8a4d5d66d434

In T268645#6645735, @Xqt wrote:

Looks like it is the same as T192912

Due to

if code == 'failed-save' and \
   self.action == 'wbeditentity' and \
   self._is_wikibase_error_retryable(result['error']):
    self.wait()
    continue

it seems that action is not 'wbeditentity'; any idea what it was?

Either https://www.wikidata.org/w/api.php?action=help&recursivesubmodules=1#wbcreateclaim or https://www.wikidata.org/w/api.php?action=help&recursivesubmodules=1#wbsetqualifier I think.
We have a whole list of possible Wikibase actions that trigger a write. If I look at self.write = self.action in {....] that seems to be quite complete. Maybe in the start of the init define a list of normal write actions and a list of wbwrite actions and update both checks to use these lists? First check would use both lists and the code you pasted the wikibase list.

According to this test, there are several actions that might emit 'wikibase-api-failed-save' as message.
https://github.com/wikimedia/Wikibase/blob/e388e5b69ee0487566d7a8a77196ac0056f49747/repo/tests/phpunit/includes/Api/ApiUserBlockedTest.php

The test seems to be for blocked users, but maybe the message is used elsewhere as well.
Shouldn't they be all checked in:

if code == 'failed-save' and \
   self.action == 'wbeditentity' and \
   self._is_wikibase_error_retryable(result['error']):
    self.wait()
    continue

instead of 'wbeditentity' only?

Change 643491 had a related patch set uploaded (by Xqt; owner: Xqt):
[pywikibot/core@master] [bugfix] _is_wikibase_error_retryable rewritten

https://gerrit.wikimedia.org/r/643491

Change 643491 merged by jenkins-bot:
[pywikibot/core@master] [bugfix] _is_wikibase_error_retryable rewritten

https://gerrit.wikimedia.org/r/643491