In Sprintr, on Tab 'Wall': Commenting on a story-comment by typing some text and concomitantly attaching a document. Upon pressing 'Post comment'-button the text is lost (=not posted) and the document is not found under the documents-tab. However, in some rare occasions the document is found under tab 'documents' while the text is lost. Surprised that this potential bug has not been mentioned earlier (see also comment).
Have you tried submitting this as feedback in Sprintr itself (the black feedback rectangle on the right) ?