Aha, found it!
It is the "save as new question" the one missing the @PLUGINFILE@ conversion !
- create quiz
- add true/false question with images in question text, general feedback and true and false feedback (save it)
- edit the question and without changing anything, click on "save a new question"
- One new question is created with all the images using @PLUGINFILE@
Current (wrong) result:
- One error about URL not found happens (I commented that yesterday at
- One new question is created but all the images are using "draftfiles" URLs (the conversion to @PLUGINFILE@ doesn't happen)
I guess the same will happen with other qtypes, I only tested the true/false one.