[Egyptian Text] The Gardiner signs O28, P3, and T30A are not displayed

The Gardiner signs O28 / iwn, P3 / wiA, and T30A are not displayed. Instead of them, only an empty square is shown. And when I type the next hieroglyphs, they do not appear after this empty square, but overlay it:

Reproduce the issue with Gardiner signs O28, P3, and T30A, then inspect the font-rendering path responsible for displaying them and placing following hieroglyphs. Done means each sign renders instead of an empty square and subsequent hieroglyphs appear after it without overlap.

Written by the indexing model from the issue text.