Mask's keyframes disappear when closing and reopening the project

Hello everyone.

I have a problem with a Transform preset I've created, that serves to animate a mask which leads to a transition.

As you can see on the screenshot1, I have my Transform preset on the left with its mask keyframes, and the mask's form on the right.

But now, if I close my project to open it again, you can see on the screenshot2 that all the keyframes disappeared, and so the mask doesn't work anymore.

If somebody has an idea to fix that, I take with pleasure.