No actual subtitle for a tadpole growing up to a frog

What I expected to happen was...:
I expected the subtitle to say, for example, "Tadpole grows up" or the like.

What actually happened was...:
The subtitle says, "subtitles.entity.tadpole.grow_up" (see photo).

Steps to Reproduce:
1. Turn on subtitles.
2. Spawn a tadpole.
3. Wait or feed it slimeballs until it becomes a frog.
4. The subtitle "subtitles.entity.tadpole.grow_up" shows.