As of today and having few updates from the begining of this week (Ubuntu core etc…), today i did transfer 2.8GB to my USB dongle and Wow the speed was a lot more slower than usual and the transfer bar matched the blinking of the USB dongle.
To be sure i did the same (to test) at home and it worked too (same updates of the week)
So it seems that Ubuntu have fixed the problem 
For references: I am still on U-M 16.04.5 (LTS) both at work and home USB formated as ext4 and no dongle died during the experience.