I will make a video later about my problem but i think is hard to know if that can be fixed. (After a power failure USB sticks mining again without i have to be there to restart again).
If your USB miner is not a separate power from the PC or USB HUB unreliably powers off, then yes, bfgminer will lose sync with the USB device. There will be hundreds of lines about FutureBit write error and messages about FutureBit trying to restart the ASIC. Is this what you're referring to? The quickest way is to quit and restart bfgminer. This would point to hardware issues out of the USB ASIC though. Kind of a rare case, don't you think?