Reminder to Tim after our talk at the Moodle Stand in Barcelona.

If a teachers edits a question by clicking the edit question link in a quiz, a new version is created from that question. That is not visible for the teacher, since the page stays on the same version after saving the changes. The obvious conclusion of the teacher is that the changes are not saved. The changes are only visible for the teacher when searching the question in the question bank.

The new version is not used when regrading existing attempts, which is different behaviour form before versioning existed. It's hard or impossible to regrade attempts with errors in the questions this way.