My Minecraft version is
1.13. I've created 2 worlds with the same seed: one for creative and one for survival (everybody do like this, i think:) ). In creative world I found some end citites, but when I went to the same place in my survival, the end city wasn't here.
Then I tried the following: I copied folder with survival world, switched to creative in it, found another end city... And when I went to this place in survival here was nothing. Why? I always thought, that the same seeds give exactly the same worlds.
Important note: Of course, I've checked the
Generate structures option. Few end cities, that I found in creative, generated in survival too. So, at least they can be generated in my survival world at all.
BTW, I noticed exatcly the same issue with shipwrecks.