I created a 1.17.1 world with the -528827487 seed.

Then I updated the world to the 1.18.1 version

Used eyes of ender to go to the -9700 64 20755 coordinates.

The eyes of ender indicate there is a stronghold at -9700 60 20760

What I expected to happen was...:

To find a stronghold at -9700 60 20760

What actually happened was...:

There in no stronghold at -9700 60 20760.

I checked using spectator mode.

Steps to Reproduce:
1. Create a world using the -528827487 seed in version 1.17.1
2. Go to coordinates -9700 60 20760 and render the area. Notice there is no stronghold close. Throwing an eyes of ender confirms there is no stronghold there.
3. Open the game in version 1.18.1 and convert the 1.17.1 world to 1.18.1

4. Open the world. Throwing an eye of ender indicates there is a stronghold nearby. There is no stronghold to be found

Please note: creating the world in 1.18.1 in the first place does generate a stronghold at this location.

Attached are 3 screenshots:

1.17.1.PNG is a screenshot of the -9700 60 20760 coordinate taken in 1.17.1

1.18.1 after upgrade1.PNG is a screenshot of the -9700 60 20760 coordinate taken in 1.18.1 after an upgrade. Note the eyes of ender lead to a place with no stronghold

1.18.1.PNG is a screenshot of the -9700 60 20760 coordinate taken in a world created in 1.18.1 with the -528827487 seed. You can see there is a stronghold here.