I'm using a Huawei Y7 Android 8.1.0. Everytime I select share for a PDF or DOCX file and select whatsapp or viber, the file gets renamed to a longer file name. In Whatsapp it shows 'NULL' in the thread. When opened within Whatsapp it shows long file name. Does anyone know how to stop this. It happens for file names less than 8 characters. My issue is I want to share the file with the name I have given but not a long meaningless code. All software including android and apps are updated. App caches cleared. Can anyone help?