To Reproduce

Steps to reproduce the behavior:

1. Add a paragraph block
2. Add normal, bold, italic text sequentially
3. Tap backspace button to remove the text

Result:
The active state of format buttons don't change

4. Try adding new text

Result:
The new text added doesn't match the active format Buttons

Expected behavior

1. Add a paragraph block
2. Add normal, bold, italic text sequentially
3. Tap backspace button to remove the text

Expected:
The active state of format buttons should change according to the caret position

Screenshots
Download to see the screencapture:
format-buttons.mov.zip

Smartphone (please complete the following information):

• Device: [iPhone XS]
• OS: [iOS 13.3]
• Mobile Gutenberg Editor Release 1.26, 1.25, 1.24