The sound doesn't match the characters' lip movements.

It indicates that a previous version of this specific episode (released by the same group or others) had a technical flaw, and this version is the . 🔍 Why a release is labeled "PROPER"

A "proper" release is issued when the initial upload contains one of the following issues:

Artifacting, dropped frames, or encoding errors.

Indicates the source is a Blu-ray Disc (BD) rather than a TV broadcast, typically offering higher quality and uncensored visuals. MP4: The video file container. ✅ Summary

If you see in a file name, it is almost always the best version to download , as it solves a known problem found in the "Internal" or original release.

Missing lines, poor timing, or major translation mistakes.

Likely an abbreviation for the anime title (e.g., Shinmai Maou no Testament or similar, depending on their naming convention). EP 12 END: The final episode of the season/series.