I schedule a post and for some strange reason, WordPress occasionally treats it as a Draft version and sticks it in the Draft folder. It’s more a random occurrence than a regular deal. Maybe 5 – 10% of posts, or less, I schedule wind up being put in the Draft folder even though I scheduled them using the Schedule option and including a date and time. I always double check when scheduling posts.
Happens a lot more on my laptop than phones although I post more on my laptop than I do on the phones.