QSerialPort occassionaly fails to read high speed data from VCP and will hang

I am using a device transmitting at 600Hz to a Windows 10 computer. The problem is QSerialPort has random timeout's where waitForReadyRead(1000) returns false or waitForReadyRead(-1) will hang forever.

This problem can be reproduced on the Qt Terminal Example ([QT_INSTALL_EXAMPLES]/serialport/terminal) which uses the ReadyRead() signal, the signal will simply never be fired in some cases when the port is opened and application waits forever. I am unable to reproduce the problem with other Window's Terminal programs eg. HTerm, RealTerm. 

I am using the Windows built in driver as recommended by ST on their website. 

Using Serial Port Monitor on the Qt terminal example when the program hangs I have this output: pastebin

Output from a test program (program included in link) gives this behaviour: pastebin