Style/Language/Japanese currently says this (and seems to have said something similar since it was first created in 2010):

For names and titles originating in Japan, non-Japanese characters should be capitalized as intended by the artist or label.

Although the Japanese script has no capitalization, it is very common for Japanese titles to contain characters or words from other scripts. Japanese artists have a tendency to choose capitalization and punctuation for aesthetic reasons, and to be very consistent regarding case over all releases. For this reason, words in the Latin script on a Japanese release should be in the same case as on the album art if other available sources, such as official discography or record label pages, are consistent, not normalized according to English or other capitalization standards. This applies even if the whole title is in English or another non-Japanese language, as long as it is consistently written in the non-standard way.

Style/Specific_types_of_releases/Soundtrack says this:

Consider text such as "Original Motion Picture Score" or "Music from the Motion Picture" as release subtitles.

Many Japanese video game soundtrack cover images include text like "Original Sound Track" in a different (often smaller) font on a separate line. A few examples:

• https://medium-media.vgm.io/albums/02/20/20-1196235967.jpg
• https://medium-media.vgm.io/albums/63/36/36-41d96d17fab0.jpg
• https://medium-media.vgm.io/albums/58/21985/21985-1293894126.jpg
• https://medium-media.vgm.io/albums/14/541/541-1413383864.jpg
• https://medium-media.vgm.io/albums/02/8020/8020-f31ed6c4312a.jpg
• https://medium-media.vgm.io/albums/52/525/525-1361215006.jpg
• https://medium-media.vgm.io/albums/39/293/293-1252765569.jpg

I interpreted these images as demonstrating intent for the "Original Sound Track" text to be viewed as separate from the main title, i.e. following the soundtrack guidelines, but several very experienced editors on edit #117002372 argue that the Japanese guidelines indicate that a colon shouldn't be added in these cases.

I've seen other disagreements about punctuation in Japanese titles in the past. I think that much of the confusion stems from the way that the guidelines mention that punctuation may be chosen for aesthetic reasons, but then only instruct editors to preserve capitalization.

Could the interaction between these two sets of guidelines be made clearer, ideally by adding a sentence to one or both? I think that something like, "Do not add punctuation unless it is printed on the release," would make the Japanese guidelines much clearer, if that's indeed the correct interpretation.