Reportedly only happens with BP but I don't see any reason for why that would be.
What seems more likely is that the respective code is actually broken in another way without BP, e.g. the sound is always killed before the touchdown cause the player isn't continuously falling during teleport in vanilla whereas they are with BP. Or it only breaks if there are other sounds playing at the same time (which is far more likely with BP cause it doesn't kill all sounds on dimension change).
Not really sure, either way, calling playSound within update may cause a ConcurrentModificationException, regardless of whether BP is present.
https://github.com/Johni0702/BetterPortals/issues/513
AFAICT it's calling
playSoundfrom withinITickableSound.updatewhich causes this: https://github.com/kegare/Skyland/blob/edefa31d117c3d19c911162de937cf8962396c25/skyland/client/audio/MovingSoundSkyFalling.java#L48Reportedly only happens with BP but I don't see any reason for why that would be. What seems more likely is that the respective code is actually broken in another way without BP, e.g. the sound is always killed before the touchdown cause the player isn't continuously falling during teleport in vanilla whereas they are with BP. Or it only breaks if there are other sounds playing at the same time (which is far more likely with BP cause it doesn't kill all sounds on dimension change). Not really sure, either way, calling
playSoundwithinupdatemay cause aConcurrentModificationException, regardless of whether BP is present.