@tw-hx We did not introduce this issue or make it worse. The issue was present in the form you experienced it prior to our November 17th release. We did not cause contacts to be shared when the stock OS was not sharing them and the checkbox was unchecked for everyone despite it sharing them. The commit message was not properly updated for the current state of things when it was merged. They had kept an older message from the initial change. Read the discussion at https://github.com/GrapheneOS/platform_packages_apps_Settings/pull/299. The whole point of the change was trying to fix the upstream issue you're experiencing.
You do not understand what we changed or why, and if you refuse to listen and read the past discussion about it to realize that people experienced exactly what you did and the checkbox was already off by default before our change. Our change was intended to make the low-level default aligned with what the checkbox shows. We didn't introduce any part of the issue. We did not successfully fix it in every case because in some cases the value is set with the same exception before our change kicks in.