Been having the same problem: MIDI notes recording earlier than when performed. It’s a big problem and seems to just get crappier as time moves along. From I can gather, it’s a WINDOWS clock issue. The longer the PC stays on, the more the timing issue will get worse.
Steinbergs suggested the following fix:
"The first thing I want you to do is reset the program preferences back to a default setting to make sure that isn’t causing the issue here:
You can manually reset your application data by opening your File Explorer: C:\Users\Username\AppData\Roaming\Steinberg then move the folders that say Cubase 9.5 or any earlier version of Cubase you see to the desktop.
*If you don’t see the AppData folder, you must select View > Options > Change folder and search options. Select the View tab and, in Advanced settings, select Show hidden files, folders, and drives and OK.
Restart the computer and then launch Cubase again. Be advised the load time will take longer as it will be rescanning everything just as it did the first time you opened the program."
What’s interesting, is that this fix seems to work but it only lasts for a short time before the MIDI notes start slipping ahead of the actually performance. I can actually see the notes planting early as I play.
I wish someone (MS or Steinberg) would fix this issue.