I made an example at https://glitch.com/edit/#!/sprinkle-hazel-meadowlark?path=index.js%3A18%3A17
You can move the cursor downwards with keyboard (myblock -> mytag -> other stuff).
And when you try to move the cursor upwards instead, you will find it stops at mytag.
And if you replace the content of mytag from text* to paragraph, the issue disappears.
But I want to keep the content as text*, while no problem for the cursor movement. How could I make it?