QSerialPortInfo getting duplicate serial ports with null characters

This is on my slightly dodgy laptop that has had other problems before with Qt and serial ports (not picking up when they've been disconnected), but this seems to be something else.

Serial port listing was working fine earlier, and I assume restarting the PC would fix it, but for some reason Qt is getting duplicate serial ports (in this case duplicates of COM 1 and COM2, COM 1 is a physical serial port and COM2 is an FTDI USB cable) which it is detecting at COM1\0000 and COM2\0000. Other programs are not getting these ports.

I've checked in hardware manager, only the 4 valid ports are listed. I've checked in regedit under \\HKLM\HARDWARE\DEVICEMAP\SERIALCOMM and there are 4 keys:
\Device\BthModem0 > COM220
\Device\Serial0 > COM3
\Device\Serial2 > COM1
\Device\VCP0 > COM2

I've attached a screenshot showing this issue in a breakpoint, QSerialPortInfo has returned the data and thinks the port is valid somehow.

No file included to reproduce this as it will happen with the sample projects provided as part of QSerialPort