If share a Pages document via iCloud and this document is placed in a "sub-folder" in iCloud, f.ex. in a folder called "Pages" - it gives an error when you try to upload the file as an assignment answer in Itslearning.
This is not a BUG in Itslearning, but a bug in the Safari browser on iPad.
We are not able to fix this, unfortunately.
See also attached PDF-file for more details
If you place the same document in the "Root"-folder of you iCloud - root-level is when you see the "Pages" folder in iCloud - and then try to upload the file as an assignment answer, it works OK.