Is it acceptable to use "Just wondering" as a question? [duplicate]
It is acceptable to say it but it would be more conversational in tone and style so it would be NOT be appropriate for a formal document.
Phrasing the question in that fashion might be perceived as being diplomatic, perhaps in a situation where you are asking someone for something you know they have not done! "I am just wondering if you go around to writing that report..." but there may be an inference of an implied but subtle criticism.