SOS Morse code by HALs are inverted. And the pauses between letters are too short.

[quartz plume]

"Typo" + "Sound" is really a strange combination of categories, but I suddenly realized that the dits and dahs are actually inverted - SOS became OSO as a result, and the following message is affected as well. (And I'll be triggered every time I hear it again, so I'm reporting it as a bug here.)

Also, the actual message is hard to decode as it seems the pauses between letters are too short. This made some letters hard to distinguish; for example, the substring "ies" became six dahs (should be dits, see above) with almost no pauses in between, and the actual letters can only be inferred from the previous ones to make a proper word. The standard pause lengths might be too long for this message though, but if this message is meant to be actually decoded, you might want to make the pauses a little more longer.

I looked at another recording sample and found the pauses are unstable; in another snippet, "ies" became "ss" as there is a pause before "s" but the pause essentially doesn't exist before "e". Is this audio actually dynamically generated instead of one prerecorded file, or the playback is somehow affected by my gameplay?

[past ocean]

dynamically generated, actually

let me take a look at this

indeed, you are correct