Same here except on PC.
Can't engage Nav or managed Modes (Alt or Speed) when I made manual changes prior.
The Buttons do click in but doesn't trigger the managed modes.
Also I noticed for a DIR I have to go back to the FPL page and activate a temporary change for the DIR to happen. But then I have the above mentioned problem.
Love the plane so far especially the EFB and Takeoff Calculator.
Thanks for the great Work