Hello toto_riina79 ;
Thank you for taken the time to post your question. The problem you described is that you have installed a USB/video display to be able to use 3 different monitors. And you are able to see all three displays, but when checking the Intel Graphic properties you can only see two display.
This is because the Intel graphics has only two display outputs. And for the USB to video you had installed additional drivers and software. I will recommend to check with the manufacturer of the USB to video adapter to see if there is a way to manage all three at the same time.
As for Intel it will only manage two monitors at a time