See T400013: VisualEditor deletes list-defined references if there's a reference containing an ISBN and magic linking is enabled and T400038: VisualEditor deletes list-defined references when editing one of them
We want to understand how severely this bug affected the projects. The critical code was deployed to the last tier of production servers on Thursday 17th of July, the bugfix deployed on 21th of July in the UTC morning.
The current plan is to run a script to look through edits and identify changes that match patterns with vanishing contents.