Steps to reproduce:

1. Create a quiz containing one matching question with two hints, and using Interactive with multiple tries behaviour.
2. As a student, start an attempt at the quiz. Note that the question state is shown as 'Tries remaining: 3'
3. As admin, regrade the quiz.
4. As student, resume your attempt.

Expected result: No visible change to the question.

Actual result.

5. It now shows ‘Tries remaining {$a}’ instead of 'Tries remaining 3'.
6. If you submit incorrect or partially correct answers as many time as you like without limit. (Tries remaining goes -1, -2, -3, …)

I suspect that the underlying bug in the regrade code has been present for a long time, but lay dormant until MDL-72890 was implemented.