Hi all!
It looks like this behavior is expected for Axure RP 9, but I can confirm that this is different than it is in Axure RP 8. With Axure RP 8, choosing the “Lock to Master Location” drop behavior when creating a master has the master use its current placement on the page to create a custom location for the widget(s) within the master. In Axure RP 9, applying “Lock to Master Location” drop behavior uses the master widgets’ already-defined location within the master to place the master on the page. If you make a page’s widget a master, and then immediately change the drop behavior to lock to the master location, the master’s widget will go to (0,0), because that’s the default location for the master’s widget, and the page is using that to place the master. It’s similar to how converting a widget to a dynamic panel automatically gives that widget a location of (0,0) in the dynamic panel.
With masters in Axure RP 9, you’ll want to define the widgets locations in the master, and then use the “Lock to Master Location”. That said, I can see how this change would feel different and/or unexpected compared the process in Axure RP 8, and I’ll file a feature request with our respective teams to review this.
If you run into anything else in Axure RP 9 that you would like to see changed or improved, please email us at support@axure.com so that your feedback is seen as soon as possible. Thank you!