Not able to save files on Google drive via files app on iPad

Hi there I'm having a very frustrating time not being able to save files (pdf) on the files app using the google drive function. I will 'markup' a document using my stylus and when I go to save the file in google drive it appears to be greyed out and has a red circle with a 'cancel' icon on it. It is so frustrating because I spend lots of time editing the document only to have it all gone! The file seems to duplicate itself when it 'saves' but I cannot access the darn thing.

Any help with this would be appreciated!