Cubase Version: Cubase Pro 15.0.30 Build287
OS: Windows 10
Issue Summary:
When an Expression Map is assigned to a MIDI track, adjusting note velocity in the Key Editor with Acoustic Feedback (Speaker icon) enabled generates an unusually high-frequency flood of Note-On/Keyswitch data. This MIDI spam easily overloads script engines in larger orchestral plugins, leading to hanging notes, stuck articulation switches, and severe playback bugs.
Steps to Reproduce:
Assign an Expression Map (using Keyswitches or Attribute/Direction articulations) to a MIDI track.
Open the Key Editor and make sure Acoustic Feedback is turned ON.
Select a note and click-and-drag its velocity up or down with the mouse.
Expected Result:
Cubase should apply a proper debounce or rate-limiting filter to Acoustic Feedback during mouse dragging, sending only the auditioned note with updated velocity—without unnecessarily spamming the Expression Map’s Keyswitch/trigger data on every single pixel of mouse movement.
Actual Result:
Cubase fires an abnormal amount of duplicate MIDI messages in an extremely short time window. This high-frequency stream chokes third-party VSTi script engines and breaks normal audio feedback.