Update 3: I rebuild the drone track as follow; inserting one clip, unlink it, put for the fisrt fade in, inserting one more clip, unlink it, inserting transition between the first and the second and so on, when i select the the transition i see this message almost all the time for all the transitions.
I have also to point out that Crossfade in my opinion should be just stuffing a track over the other track, in this way it’s more easy to control the length of the crossfade and no need to trim.
This video helped me to understand and resolve that problem: https://youtu.be/58sU2V5hos4?t=195
That tutorial is about the same issue in Premiere Pro but the principle is the same in Luma Fusion and the solution can be applied to it too.
Hope this helps.
By the way, it would be very helpful if there were a tutorial also about this issue on Luma Fusion website.