Here's the map we're talking about:
Hanlon's Razor seems to apply.
My mom never heard of Germany or Nazi or World War 2. She will happily draw swastikas during festivals.
It seems to me that a map like this is a Rorschach test—you'll see in it whatever you expect to find.
Crazy that they added such a specific detail to a map that looks like ... that. I agree with Vietnam that it has to be a deliberate move towards being nice to China.
You really have to know that it's about the small dotted line next to China. So I do get it, it can be seen as very sneaky propaganda.