In general:
After you S/R to usb from PT, move the “Shared Paratext 8 Projects” folder from the root of the USB drive to “Android/data/org.paratext.ptlite/files”
So it exists at:
“Android/data/org.paratext.ptlite/files/Shared Paratext 8 Projects”
As long as your PT 8 is up-to-date, PT 8 should happy continue doing S/R to that new location.
However given the problem report I received from you, it looks like, PTLite isn’t managing to identify the usb stick in your device. (I realized that I have just been using a fat32 formatted usb stick for testing, and so I’m going to try some other types)