Hello,
Could you post a short (few seconds) video about this? I can't really imagine what it might look like exactly.
But my guess would be that you use the classic Magic Mouse, and not Magic Mouse 2. Magic Mouse 2 is more sensitive, and the new macOS versions are trained for that, so the old ones can get a bit harder to control (at least that was my personal experience).
Regards,
Daniel Alexander Kovacs
Professional Services Consultant
GRAPHISOFT
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