Some other update:
i tested it on a laptop device with linux installed. there it works without detach problems. therefore the problem is somehow connected to the raspberry pi. i have set the raspberry usb output from 600mA to 1.2A. even though there is a usb-power-hub still in between raspberry and 1047 board so there should not be that much power consumption. still the problem sometimes occurs.
(raspi is powered with 2.5A and 5.1V like recommended)
btw. i also changed the usb-power-hub and the power supply of raspi to be sure that it's not the problem.