Tried from external flight plans and from P3D flight planner. It's random. Sometimes the plan will load and other times when you hit activate then execute, the activate reappears and execute lights up again.

No option to the next page unless you press activate twice. But still no loaded flight plan. After this when I try to manually enter the flight plan, ICAO data just disappears the second I  LSK the data.

As for IRS alignment, it will if it feels like it... it's all random. Sometimes it all works and then not at all....

I was able to get the flightplan loaded via the FO FMC. But fails from the left seat FMC. If heading function is used to intercept the flightpath, the AP will not follow LNAV flightplan.

Update. After the AP sends the aircraft around in circles it finally intercepted the magenta on it's own.