File extensions not working as expected, is this normal?

Question

In the finder, there is an option to "Show all file extensions".
So normally, a certain image file could be either "image" or "image.jpeg".
However, I have some weird files: "image.jpeg.jpeg" EVEN WHEN I HAVE SET THE EXTENSIONS TO BE HIDDEN. What I want is to remove these extensions, because they should have been hidden.
I rename it to "image", removing the ".jpeg.jpeg" and it automatically adds another ".jpeg" at the end. Finder just does that, no prompt.
Then, I remove that extension it just added, so it becomes "image". Again, no prompt, because this is the way the file should be. Finder does not tell me "Are you sure you want to rename it to .jpeg"
Now, this file is normal: its extension can be hidden or shown by the finder, rather than being unaffected. Why does Finder do this?
Is there a way to batch-remove duplicate extensions so that the extension is affected by the Finder's "Show extensions" option?

Answer 1

Does this anomaly occur with only a few files or all files?
Try creating a new user account and seeing if this happens when using that account as well.
Have you recently repaired permission?
If you are familiar with the terminal, you can use the command
ls -al@
in the directory in which this file resides and post its attributes here.