This scene is pure metaphor. The swallow (a symbol of returning home) is stuck, rusted. The extra frames allow the viewer to feel the hikigomi (引き込み) – a Japanese aesthetic term for the pull of melancholy. That is "extra quality." It is not about resolution, but about intentionality .
“Most summer anime give you nostalgia. This one gives you the wound of nostalgia while it’s still bleeding.” This scene is pure metaphor