Just updated on my Oppo Find X5 Pro and still the same problem. It's definitely a firmware issue on Fujifilm's part because it stopped working after updating to the latest firmware update.
I've given up on Fujifilm and bought one of these SD card to USB C which I can just plug straight into my phone and transfer files. It's much faster than the garbage X app and doesn't lag at all.
Au revoir X app. See you again never.