anker 4-port ultra slim usb 3.0 and saving files Adobe Acrobat Reader DC

Given: Thinkpad T490, Windows 10 Pro, Adobe Acrobat Reader DC, Anker 4-port ultra slim USB 3.0
SanDisk Ultra USB 3.0 (connected to 4-port Anker), Adobe PDF file 17MB saved on SanDisk USB

Problem: When coming back to work (e.g highlight text) on an Adobe PDF file, the file is no longer editable and cannot be saved, need constantly reopen it when coming back to work.

Suspect: Power management? Tried the same brand different USB drive. Still a problem.

Any ideas?