Cubase resets MIDI CCs to zero

I use Cinematic Strings 2 which uses MIDI CC2 for vibrato. For some reason, Cubase keeps resetting this value to 0 randomly. I turned off the option in preferences “never reset chased controllers” but that doesn’t seem to help. Has anyone else experienced this?

Are you certain that it is Cubase that is generating this randomly, and that it is not your external MIDI keyboard/controller that is transmitting it? (Just record-enable a MIDI track, let it run for a while, without playing anything, see if any unwanted CC# data is getting recorded).

Positive. My keyboard isn’t capable of sending any CCs except #1, #64, and pitch bend.