When recently going to attach multiple files to an open ticket, I used the 'Add Attachments' function and observed that the text of "100% oo" appeared. Thinking that the file had been 100% loaded, I selected OK and only the first file was attached.
Through investigation, trial and error, it appears that the 'oo' are indicators of the multiple files yet to be uploaded. I think that this section of the portal can be easily re-designed to show a more accurate upload indicator: Showing '100%' when all files aren't uploaded is misleading, and the 'oo' doesn't give any indication that they're representing 'Files awaiting upload' until they start disappearing, which can take a while depending on the file size.
A loading bar, item list or even plain text would be more accurate than leaving customers to guess what '100% ooo' means, as they won't know that only one file will be uploaded if they click OK, thinking that 100% means 'done'.
Previous suggestions that relate to this are: