Thanks for the report. Unable to reproduce this so far. Can you confirm a few things:
- In Cubase, what settings do you have in Transport / Project Sync Setup (all three tabs)
- Do you have any other MIDI going between Cubase and the S2400, or is it only MIDI clock?
- Are you using the 2021-03-17 firmware update? (from here S2400 Firmware Updates - #14 by Mickey)
- Does this happen even on an empty S2400 project? If not, could you share the project you’re having problems with.