Shift+Enter causes weird issues with code element

[jswiderski]

Is this a bug report or feature request? (choose one)

🐞 Bug report | 🆕 Feature request | Other

💻 Version of CKEditor

12.3.1

📋 Steps to reproduce

1. Open https://ckeditor.com/docs/ckeditor5/latest/features/basic-styles.html
2. Type Test and press Shift +Enter
3. Type `test`
4. Press space
5. Type `test`
6. Delete "t`" using back space and start typing works test all the time

Please also have a look at attached screen-case to get a better idea how to reproduce this issue
bug.zip

✅ Expected result

Both `test` should get converted to code elements

❎ Actual result

1. The first `test` remains unchanged
2. the second gets "code style" applied plus some weird text rewinding. Please see attached screen-cast.

📃 Other details that might be useful

Original support issue - 56930

[jswiderski]

Another use case:

1 Type whatever,
2. Press Shift+Enter,
3. Type `a`a`a`a`a`a`a`a`a`a`
It breaks after ~5 repetitions of the a+backtick.
Screen-cast bug2.zip

[jodator]

Breaks also the text transformation in a similar fashion - wrong position are used to replace quotes:

The second test should be replaced.