does the issue happen in handheld mode?
I haven't tested that. After spending 2 hours today thoroughly re-testing in docked by playing through the whole Great Sky Island up until reaching Lookout Landing, I would have to do all of that again plus more in order to definitively prove whether or not it happens in handheld mode too, unfortunately.
does the issue happen in other games?
No. I've never experienced this in other games before.
you could try deleting and reinstalling just the update data.
Thanks. After reading your comment I gave it a try. I think the reason I didn't test deleting it back when I first had the issue in January was that I didn't have Nintendo Switch Online at the time, and my save data was not backed up to the cloud. So even though I know the save data is not supposed to be wiped if you delete the game data, I was scared by the small chance I might accidentally delete my 72-hour save.
I have Switch Online now and have the save data on the cloud, so I just gave your suggestion a try.
After deleting the data and re-updating the game, I started my original save file again. The cutscenes were playing fine... but that doesn't necessarily mean it's fixed... because as I mentioned, once the game has loaded that cutscene once, It's fixed for all future playback.
So to double-check, I decided to do a very long test. I started the game on a completely fresh profile, and let each cutscene play out without skipping them. I needed to get far enough into the game to find a scene that the game hasn't yet loaded since updating. In this case, that was the scene where you first meet Ruaru outside of the Temple of Time. Everything seemed fine, and there were no glitches in that scene. However, I wasn't satisfied yet to know it's definitely fixed, because it was not a pre-rendered cutscene like the ones I've had the most issues with. So I spent 2 hours trying to rush through all the shrines on the Great Sky Island so that I could play the next 2 cutscenes with Zelda. Specifically the one where you see Zelda inside the Temple of Time, and the one where she receives Link's broken Master Sword right before you skydive to the mainland of Hyrule below. Over those 2 hours, I didn't experience a single audio glitch in gameplay. By the time I'd watched the second Zelda scene, I was 99.9% sure the audio was finally fixed. All I needed to do now was quickly rush to Lookout Landing to meet Purah, where I would play the last cutscene before turning off the game.
I reached Purah, and the in-engine cutscene that played was perfectly fine. Unfortunately though, once the pre-rendered cutscene; the one where Purah recaps everything that happened to Link up until that moment in time played, the cutscene immediately began having audio issues!
They were only minor, but as I mentioned earlier, sometimes they are minor, and sometimes they are extreme. Back in January there were not only audio-delays, but also rough audio-popping.
I recorded all the footage again. I took the part of the video where the glitched cutscene happens, and made the word "GLITCH" pop onto the screen every time an audio glitch occurs, just to make it a bit easier for you to tell when it happens. Here it is: https://ody.sh/CzUj40fCnv
I don't believe the problem is with my HDMI port. This is a new monitor I only purchased 1 and a half years ago in early 2025. The HDMI port issue I mentioned in my main post only applies to my old monitor which I was playing on in 2023.
I also don't believe the issue is with my capture card. If the audio delay was caused by my capture card, it wouldn't only be the sound effects that glitch in the cutscenes. Notice how in the first video I sent you, it is only the sound effects of Zelda jumping backwards, away from Ruaru and Sonia, that are out of sync. The actual voice lines are still perfectly in-sync with their mouths. If this was an issue with my capture card, ALL audio would be out of sync including voice lines. But they are not. I would also be experiencing the de-synced audio everywhere in gameplay, in all my games and on all my consoles. But it's only Tears of the Kingdom on the Switch 1 that has the issue.