Unable to manage my batches after having my SUL renamed

After having my Wikimedia-SUL renamed I'm no longer able to properly manage my batches.

Steps to reproduce

1. Have your Wikimedia-SUL renamed
2. Create a batch in QuickStatements 2

Expected behaviour
I should be able to manage my batches as it was possible before having my Wikimedia-SUL renamed. This especially includes being able to view a list of my batches and being able to stop them.

Actual behaviour
Batches created by me are actually created under my old username which leads to me not being able to manage them and them being not properly associated with my identity in QuickStatements. Edits made in Wikidata are nevertheless properly associated with my identity (and new username).
Also, there are now some inconsistencies in the GUI which brings me to the assumption that for identification purposes QuickStatements uses my current username except when creating batches. I'm not familiar with the design of QuickStatements so I suppose QuickStatements keeps its own database on users and uses this one to associate batches to their creators.

1. Inconsistency:

   • In the header the button bringing me to my QuickStatements-user page is labled with my new username. The button next to it (Your previous batches) links to https://quickstatements.toolforge.org/#/batches/$NEW_USERNAME.
   • In the batch page (https://quickstatements.toolforge.org/#/batch/$BATCH_ID) the meta data of the batch displays my old username, links to my old Wikidata-userpage and to a batch overview with my old username (https://quickstatements.toolforge.org/#/batches/$OLD_USERNAME). However, after the batch has finished I can still Reset errors
   • 

2. Missing functionality:

   • In https://quickstatements.toolforge.org/#/batches/$NEW_USERNAME no batches are listed.
   • In https://quickstatements.toolforge.org/#/batches/$OLD_USERNAME batches created after having my SUL renamed are displayed.
   • 

Version
Version deployed to quickstatements.toolforge.org as of 2021-01-22

Note: I previously reported this issue somewhere on BitBucket (cannot find it anymore) but received no reaction whatsoever. There are still issues related to QuickStatements under magnusmanske/wikidata-todo which might be worth migrating if GitHub is the new home for issue reports.

Start with the batch creation and management entry points shown by the /#/batches/$NEW_USERNAME and /#/batch/$BATCH_ID URLs, then trace how the old and new Wikimedia-SUL names are associated. Compare batch creation, listing, stopping, and Reset errors behavior; done means renamed users can see and manage batches created after the rename under their current identity.