Comment 4 for bug 891307

Again, the USB ID 19d2:0031 means that the device is already in the mode it should be in.

If you add your line to the rules file, usb_modeswitch will be called a second time after the mode switch, but will do nothing because there is no config file with the name "19d2:0031" ...

To see why you have trouble in the first place, we need that dmesg output (or a snippet from the end of /var/log/syslog) right after plugging the stick (give it around 10 seconds).

If you want to see in detail what usb_modeswitch is doing, you can enable logging in /etc/usb_modeswitch.conf. On the first try, disable your additional rule and have a look at the log file (/var/log/usb_modeswitch_<something>), then in a second plug attempt see what happens if you have it enabled again.