Once you turn ANNOAUTOSCALE on and add a second scale to your annotative content, that scale is added; turning off ANNOAUTOSCALE at that point will not remove any scales already added to your annotative content, just prevent additional ones from being added.
Select you annotative content, right click and choose Annotative Object Scale > Add/Delete Scales from the context menu. In the Annotation Object Scale dialog, select the scales you do not want, leaving just the one you do want unselected, and then select the Delete button. Select the OK button to ratify the change.
You will have to repeat that process every time you have content with multiple scales, if you do not want the content to change sizes, so you may want to keep ANNOAUTOSCALE turned off. If there is just specific content that you always want at just one size, you may want to consider creating non-annotative content for that.
David Koch
AutoCAD Architecture and Revit User
Blog | LinkedIn
