RTEditor/src/main/java/com/onegravity/rteditor/effects/ParagraphEffect.java
@Override
    public final void applyToSelection(RTEditText editor, V value) {
        Selection selection = getSelection(editor);
        applyToSelection(editor, selection, value);
        Effects.cleanupParagraphs(editor, this);
    }
@Override
    public final void applyToSelection(RTEditText editor, V value) {
        Selection selection = getSelection(editor);
        applyToSelection(editor, selection, value);
        Effects.cleanupParagraphs(editor, this);
    }
Make sure applyToSelection works on whole paragraphs and call
Effects.cleanupParagraphs(RTEditText) afterwards.