Possible bug?: 1.3.19b13a (477): add new glyph recipe with Cyrillic

Glyphs
1

Glyphs 1.3.19b13a (477)

Trying to create a new glyph with components using the + recipe, e.g.,

Add new glyph (Command-Shift-G)
Enter: sha-cy.sc+descender-cy.sc=shcha-cy.sc

shcha.sc gets created, but without any components within it.