On every flight I am doing from somewhere far east to far west, the flight plan will show me a line going the opposite direction, like it cannot cross that invisible border, the same thing is happening from west to east.
Here is an example of a flight between New Zealand and Tahiti.
It will happen on G1000 - G3000 - Airbus - Boeing - etc…
Same problem with or without mods
Just found this for the first time myself too. How does this not have more up-votes!? 
This is a bug and occurs along the 180 degree E/W longitude. Your aircraft should keep following your original waypoints even though the flight plan on the map shows differently. After you cross the line, the map should straighten the plan out.
Make sure you report this to zendesk.
https://flightsimulator.zendesk.com/hc/en-us/requests/new
It will do exactly as you described. I sent the bug report on Zendesk and seems to be solved.
I hope for this kind of bugs we won’t have to wait 2 month to see a fix coming.
FYI it’s not the international date line, it’s the 180 degree East/West longitude
You are correct!
current MS FLT SIM Rel → 1.12.13.0
Created flight plan between Tokyo (RJTT) to Pearl Harbor (PHNL).
Navigation path transition between waypoint 30E80 and UVIHU (on pacific ocean) makes a full earth turn back, in clock wise direction (their direct distance is around 264NM only, but path goes in opposite direction of the globe).
I’m using A320 (with some community livery)
Will try to add the flight plan here, once i can regenerate it. (anyway the NAVLOG print screen shows the currently flight plan. Also the A320 computer is displaying the transitions).
On VFR MAP , when I move slide it consecutively right left will switch between the 2 print screens shown below.
before arriving to 30E80 , we see the path goes back (1st picture)
just after passing 30E80, the path changes to (2nd screen). Aircraft will continue smootly to UVIHU (i.e. will not go back to turn the globe).
So it seems only a display problem of the path.
On flight planner was okay, just inside the sim got the problem.
“IFR from NFFN to NTAA, but looks like the sim can’t cross a point and rather travel all around the world to reach the next waypoint. At the planning stage is looking/working fine, but in game it goes wrong. Cancelling a waypoint in the MCDU doesn’t help. Also in the planning menu when you select an approach and try to delete one waypoint the app does CTD. It looks like the issue is with the International Day Line”
This was my report on zendesk in October and for me it wasn’t just a display problem that time
