Empty Base Glyph confusion

I created a glyph for ordmasculine and Glyphs 2 added an empty base glyph box. what caused this? I then created the same glyph in every permutation such as a.sups and asuperior to see if that was any better, same story.

The empty base glyph icon means that a component reference is missing or empty. You can select it to see which glyph might be missing or empty. Double click it to open the glyph for editing. You can also delete it.

Some some glyphs, such as ordmasculine, Glyphs will start with a component of a reference glyph to attempt to help, similar to what happens on creating an Aacute that will set up the glyph with two components, A and acute.

What method did you use to create the a.sups (or asuperior) glyph? I don’t recall either of those patterns using components in the initial creation of the glyph.

I just typed in the names in the new glyph dialogue.