`radial_control_modal` would only actually update the target property (via `RNA_property_update`) for the "standard" ways of confirming (`LEFTMOUSE`, `EVT_PADENTER`, `EVT_RETKEY`). When using "release_confirm" however, that was skipped, so added the `RNA_property_update` now. Pull Request: https://projects.blender.org/blender/blender/pulls/136884