The problem occurs in the following succession of events:
* Emit commands returning an answer larger than 16 bytes
* Re-enumerate USB devices without power cycle, e.g. a warm reboot of the PC
The bug can be reproduced for testing purposes with usbreset.c from
https://askubuntu.com/questions/645/how-do-you-reset-a-usb-device-from-the-command-line#661
$ lsusb|grep NFC
Bus 001 Device 010: ID 04e6:5591 SCM Microsystems, Inc. SCL3711-NFC&RW
$ sudo ./usbreset /dev/bus/usb/001/010
Resetting USB device /dev/bus/usb/001/010
Reset successful
$ echo -e "4a 01 00\n423000" |pn53x-tamashell
$ sudo ./usbreset /dev/bus/usb/001/010
Resetting USB device /dev/bus/usb/001/010
Error in ioctl: No such device
$ lsusb|grep NFC
... device disappeared
In the example above, reading 4 pages of a MFUL corrupted one single byte.
The entire buffer can be corrupted e.g. with fast-reading a MFUL EV1:
$ echo -e "4a 01 00\n423a0013"|pn53x-tamashell
c9ac17c9f5