MATLAB Serial to MIDI Communication Win7 vs. Win10

I am communicating from MATLAB to a MIDI interface using com0com to create a virtual serial port, and then using Hairless MIDI as a bridge.

I send three bytes of data, to send one MIDI message as per the MIDI standard.

Just to show you the simplest variation of my code...

COMport = serial('COM19','BaudRate',31250);
fopen(COMport);

fprintf(COMport,'%c',180); 
fprintf(COMport,'%c',102); 
fprintf(COMport,'%c',00);
fclose(COMport)

On Windows 7, this works perfectly, all bytes are received and the MIDI messages are execute.

However, now that I have sent this over to another machine running Windows 10, I have encountered some issues. The Serial bridge still receives 3 bytes, but returns

1 Error: Got unexpected data byte 0x3f

2 Error: Got unexpected data byte 0x66

3 Error: Got unexpected data byte 0x0

Strangely, the first byte is always 3f (63 decimal), but the other bytes are the correct values

I've looked on the Hairless/com0com sites and confirm they are compatible and signed for Windows 10. The only difference is I am running Matlab 2017a on Windows 7 and 2016b on Windows 10.

I know this is a pretty specific situation, but you never know whether someone else as had a similar issue! Any help would be greatly appreciated.