Actually, I had the same problem, charging only to a maximum of 87% or less (using two different usb charges and the 4 usb ports of my home computer and the 3 of my portable, so I doubt it is a fault in the USB chargers) and issued a ticket at IREX, their response was that this was not normal and that I should send my reader for testing.
I strongly suggest that everyone with this kind of problem should at least create a ticket describing his problem at IREX. In my case I got a reply withing one day.
I have send now my IREX for inspection and I'm waiting now to get it back. One side remark, on this moment I'm already waiting for 2 weeks, since they have confirmed that they have received my unit (maybe it is not so good idea to suggest creation of a ticket because it would probably increase the backlog
). Is there someone here with some experience of the repair time at IREX?, 2 weeks is a long time to wait.
Thanks
Mertens Marc