Hi Rob. This is something I remember being reported by a user a while ago, but I was under the impression it had been resolved. Regardless it is not an issue we are able to replicate with the Scaler 3 v1.0.7 VST3 plugin in Ableton Live 12 on Mac OS 15.
If this keeps happening after rebooting your computer it might be worth trying a clean install.
Are you on Windows of Mac OS? Clean install instructions for both are at the bottom of the ‘Known Issues’ forum page, so let me know if this issue continues after following those steps: