unexpected mobile reboot on serialUsb reconnect

[buttairfly]

The serial connection via USB has a major bug on some of the tested mobiles:
Samsung Galaxy S2
Modelnumber: GT19100
Android: 4.1.2
ROM: XWMS2 NeatROM v5.6
Kernel-Version: 3.0.31-1484249

At the end of the first connection, in the UsbSerial::close() function:
usbConnection.releaseInterface(usbInterface) returns false. This means the claiming of the usbInterface could not be freed. In the next attempt to connect to the usbDevice, no fail is detected during setup but when in UsbSerial::receive() function the usbConnection.bulkTransfer(...) is executed, the mobile reboots.

It does not happen, if the Usb cable gets unplugged and replugged again.
It does happen on the second try to connect to usb (while connecting to usb is possible -> no other error is detected). Inbetween it is possible to connect via bluetooth without any problems.