I have this happen very often, too often and I don’t know why. I have auto save on and when I exit scrivener it automatically saves then when i go to open my document again it presents me with two options, one of them being an edit conflict.
To be clear, Scrivener is not creating this file. This is what cloud services do when they find that both the local copy and the server copy of a file have changed. The cloud service can’t tell which version is correct, so it flags the conflict to notify the human.
So the first question is what cloud service are you using? Is this just a save/re-open operation, or does something else happen in between?