Lexical version: 0.3.7

Steps To Reproduce

1. Open the playground page https://playground.lexical.dev/
2. Create two paragraphs
3. Select the first one (from the very end, e.g. use double-click)
4. Apply any block format (e.g. heading or quote)

The current behavior

The selected paragraph and the paragraph next to it are converted into the new format.

The expected behavior

Only the selected paragraph is converted into the format. The paragraph next to it remains as is.