That is because a number of code points in the PUA are used by the Complete Composites feature.
Set the Glyph Overview to use Decimal code-points (Ctrl+J)
If you have used any of these code-points (at the start of the PUA) for your bows, they will be used to compose accents for Uppercase accented composites.
57365-57378 Low Profile Diacritics for Uppercase or Small/Petite Capitals
Low profile diacritics are useful in some fonts for smaller accents above capitals.
I think you can solve the problem by removing the code-points for the bows. If you have used OpenType features for them, they use glyph names, not code-points. However, if you need users of your font to insert these code-points from the PUA using a character map, then they will need code-points.
In that case, either assign different code-points in the PUA, or copy all of those glyphs, remove the code points, then complete composites on the Uppercase Latin glyphs, before pasting the code-points back with Paste Special.