conflicting/blocking styles are getting merged when pressing backspace in the next paragraph

[IvanIhnatsiuk]

Describe the bug

Conflicting/blocking styles are combined when the backspace key is pressed in the next paragraph with paragraph styles. So, let's say that we have a blockquote style in the previous line, and we press the backspace key to move the text from the second paragraph to the first. It combines conflicting styles in a single paragraph.

To Reproduce
Steps to reproduce the behavior:

1. Open the example app
2. Toggle the blockquote style and type any text
3. Press the enter
4. Toggle H1 style
5. Type any text
6. put selection on the start of the H1 line
7. Press backspace

Expected behavior

Conflicting/blocking styles should not be merged

Screenshots

Screen.Recording.2025-11-24.at.18.26.23.mov

Screen.Recording.2025-11-24.at.18.25.09.mov

Device (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[szydlovsky]

The issue has already been found and fixed by chance in iOS codeblocks; #253
Will be there in the next release 🎉

[szydlovsky]

Specifically this commit: 7df0db1#diff-78d86a8dc660896720f266f3abd146803e07b3bb7f004d812cc73ffe90ec00a9

[szydlovsky]

Reopening, the issue is also present on Android