Ancient City not located correctly

Summary: I wanted to look for an ancient city and I used the "/locate" command, it showed me a coordinate and I went to it. and I found no ancient city. however, it showed a different coordinate the next time I used the command. I went to it, dug a hole, and I found an ancient city.{}

Steps to Reproduce:

1. Create a new world using this seed: "8624896", and enable cheats
2. Use the "/locate ancientcity" command
3. Go to the coordinate it tells you (it showed me "-328, (y?), 136" the first time, The second time, it showed me: "-216, (y?), -296")
4. Dig straight down until you notice some sculk patches, then stop. (-328, (y?), 136) 
5. Go to "-216, (y?), -296".
6. Dig straight down until you notice an ancient city.

Observed Results:
I only found some sculk patches on the 1st coordinate (-328, (y?), 136) I told you about, on the 2nd coordinate (-216, (y?), -296) however, I found an ancient city.
Expected Results:
I would find an ancient city on my 1st coordinate.