Why is my text upside down?

Text on my schematic is displaying upside-down

Starting in Version: 18.0
Up to Version: Current

Solution Details

Go to Preferences ► Schematic ► Graphical Editing ►uncheck (or maybe check) the box for Display Strings as rotated.

This preference setting can cause the manually positioned designators to display upside-down when the component has been rotated 180 degrees. 

You can read more detail here:
https://www.altium.com/documentation/altium-designer/sch-dlg-schprefsform-grapheditschematic-graphical-editing-ad

This setting works in conjunction with the Autoposition  setting, so you may also need to check the part properties for the strings / designators of your component.  You may need to check (or uncheck) the Autoposition field.

If a designator is manually moved, it disables Autoposition.  You can read more detail in this documentation:
https://www.altium.com/documentation/altium-designer/sch-prop-partpart-properties-ad#parameters