That's a very unstrict strict rule You'll find that Ho Chí Minh City is served in a pattern that is HND-SGN-NRT-YVR-NRT-SGN-HND then typically the frame will do a few PEK and GMP runs from Haneda before repeating this pattern This will change with the summer schedule as YVR is getting Skysuite and SGN is not. But looking at departure times the frame arriving in SGN from NRT will continue to return to HND, and vice versa.

You will see the same on Singapore, that frames coming from Narita returns to Haneda, and vice versa.