"PrioritySetter" uninstalls itself?

1. Launch ModAssistant 1.1.32 for a 1.31.0 installation of BeatSaber
2. in the mod list, tick "PrioritySetter" (1.2.0), and hit Install Or Update.
3. The "installed" column says 1.2.0, suggesting it worked.
4. Quit and relaunch Mod Assistant.
5. Now the "installed" column only says "-" for PrioritySetter.