[richiebee]

Is it writing the MIDI data in Cubase accurately?

If its only a monitoring issue, I would turn off the monitoring of the track you're recording (you can do this in the track inspector), and be done with it. If its not writing the data correctly in Cubase, you need to take it further.

Have you tried re-starting your computer/Cubase and try starting a new project?

Is it a desktop or laptop computer? Do you know how fast the hard drive spins? I don't suspect that has anything to do with your problem here, but its handy to know.