Editing export problem

Hello everyone.
I record films from the TV then I edit or delete, among other things, the ads and cut the beginning and end.
I export to mp4.
I’ve been doing this for a long time but for 2 or 3 days when exporting the edit, the film is exported but entirely, that is to say as originally, my edit was not taken into account.
Looks like I exported the initial video into the playlist.
I must have accidentally touched a function but I don’t know what.
Thank you for your help

Are you doing your editing in the timeline? Maybe you changed the option of what to export (“From”). If you are editing in the timeline, make sure you choose to export “From Timeline”:

image

Thank you very much for your help.
In fact instead of Timeline, I had reading list but on the other hand Timeline was not present in the list.
By persevering I don’t really know how but timeline is now present in the list and selected.
thanks again