Structures that appear in Creative mode do not appear in Survival mode, for the same seed.
This is similar to MC-134729, but with the variant that I have two saves of the same seed (one with creative enabled, one with survival only)
Seed - 3276748543811363333
I have two worlds using the same seed. In creative, an end city generates at 1344, 368. However in Survival nothing appears.
I have inconsistently encountered this issue with other structures in other seeds. For example, this seed (-955523361464072251) a woodland mansion may or may not appear at -450 320 (survival mode). This is a good testing seed because the mansion is so close to the initial spawn point.
Linked issues
duplicates
Comments

I tested it over 20 times. Generating a world in Creative/Cheat mode ALWAYS generates the structure. Survival is about 50/50.
-955523361464072251 is my test seed (A woodland mansion should appear at -450 320 )
This is still MC-109311 / MC-134729. Gamemode likely isn't affecting the generation, just chance that the creative world spawned the structure.