Hi Duncan,We've been having some problems with this recently as well. We tracked it down to websites sometimes sending the wrong Content-Type for PDFs, e.g. "application/octet-stream". This used to work on iOS 12 but seems to have stopped working at some point with iOS 13. I am tryng to determine a work around but haven't got there yet.Am interested to know if this matches what you're seeing and if you managed to work around it?Thanks,Chris