Hi Mark, thank you for this report. We're currently investigating the extent of this issue in Cubase 10.5 (as well as within previous Cubase versions) with both MPE and standard MIDI controllers to locate the source of the issue. We're able to reproduce a similar issue internally, but have found that timing appears to shift when attempting to record MIDI notes over a longer duration (as opposed to a consistent length of "latency").
If you have the means, could you please attach a .gif or video of how this issue is manifesting with your setup? Please feel free to send anything over to our support team in a new ticket, which will help us to keep track of this issue.
Further to my previous reply, please try connecting your ROLI Blocks via USB to see if the issue persists. We're currently only able to reproduce this issue with devices connected via Bluetooth, so it's likely an issue with the way Cubase is interpreting MPE data sent via Bluetooth. We're continuing our investigation and will be reaching out to Steinberg for further information.
We also recommend reaching out to Steinberg's support team who may be able to assist with a resolution.