Despite the setting for embedding videos into the feed being disabled, all YouTube links are actually embed links instead of regular ones. This is regardless of the underlying posts using regular YouTube links.
Example post: https://lemmy.world/post/6127532
When viewed in Safari, the post links to https://www.youtube.com/watch?v=5pYeoZaoWrA.
When viewed in Avelon, the post links to https://www.youtube.com/embed/5pYeoZaoWrA.
If the YouTube app is not installed, opening the YouTube link from Avelon will lead to a highly disruptive embedded version being opened in Safari.
Avelon version: 1.0.7.3
iOS version: 1.7.3
Device: iPhone 13 Pro
Thanks for all the info! You’re right, this is a result of the youtube embed feature. Even with the option disabled, the app still does some preprocessing to get embedded links so you don’t have to reload everything in case you turn it on. I’ll look into converting the links back if you open them directly in the browser