I did multiple tests on this issue and got very strange, randomized results per world. In the attached video is my survival world (seed: -1584777949) that was created in the 1.16 (Nether Update) release. I defeated the Ender Dragon in 1.17 which worked fine but in the same version a few days later every time I return to the End I am sent all the way to the outer islands, specifically the void below them, in the same coordinates each time. I moved over to a brand new world (seed: 397150554) to test in creative mode and got similar results but the different spawn location happened before the Ender Dragon was ever defeated. One final test was in a world (seed: -1767955710) made the day 1.17 released and nothing abnormal occurred, it was working fine. It seems to be just a random occurrence per seed, but more testing should be done such as copies of an affected world and a new world with the same seed. I was playing Bedrock Edition on the PlayStation 4 console and am not sure if this is present in any other platform.