Fadding between Fusion Clip and Normal Clip

I have a strange problem with fades between a Fusion clip and a normal clip. When I put a cross dissolve between the two, everything is ok at first, it fades cleanly between the two.

But when I save and open the project again, the cross dissolve is only half functional, one of the two clips is not faded.

When I look at it in Keyframes, I see that I lost keyframes after reopening and the bar also doesn't pull up anymore.

Does anyone have any troubleshooting ideas?

It looks like you have negative frame numbers in your comp. try and not let that happen, try to keep all frames positive. If you take a Fusion comp and drag the start to the left on the Edit page, that will cause negative frame numbers and can cause issues. Try fixing that in your Comp and see if it helps.