It happened again here too…
This is very serious. A hotfix on 4.12 already fixed an error related to data on components, and now this…
I never seen a mesh disappear on 3dx max, or a layer disappear on Photoshop, or a function disappear on Visual … but it’s the second time I see data disappearing on Unreal Engine. I really don’t know why, but for me is clear that the storage system is not good, it appears to be messy… I mean, for me, it’s completely unreliable.
(And I insist that it doesn’t happen when the editor is closed or opened. The cause happens while you are using, but the data are still in memory, so you only see when you restart the editor. See my answer below.)