Great Circle Mapper shows the following when I enter the 2 cities:
Code Source Location
DIG unreliable Diqing, CN
LJG unreliable Lijiang City [Lijiang], CN
(my emphasis added)
I think it may have something to do with the fact that Great Circle Mapper is getting its location from an unreliable source?
Cheers
ps, if you drive at 340 miles / hr, then the data is correct