Feedback layers reset automatically the default settings

Hi everybody

I'm developping a module using many exercises such as drag and drops, multiple response...

The settings I use for the feedback layers are following: the only trigger is "change the state of next button (customised button, not the player button) to normal when the timeline starts".

So the learner clicks next on the base layer (=on the screen of the exercise, as he can click on the base layer)

The problem is that each time I edit the exercise, automatically, the default settings come back: "Hide layer this layer when the timeline ends" and "Jump to next slide whent the timeline ends".

How can I solve this problem? It take me many time to delete this triggers each time I edited an exercise...

Thanks in advance