Hi hang-single,
You're very welcome.
Even if I can explain the problem, it doesn't mean it has to stay that way. So thanks for the question in the first place!
I will file a report that the auto symmetry selection could be optional, and that would allow for the functionality you are after.
If you like to support this, please "Share Your Ideas" here
https://www.maxon.net/en/support-center
Thank you!