FMC U11 on B737NG

[flyby797]

Our FMC's on our B737NG fleet are equipped with the latest U11 software version. I noticed the following and wanted to know if anyone experienced the same "thing":
Let's say we use RTE 1 (RTE 2 is left empty). In flight or on the ground before departure, we fill out the ALTERNATE DESTS pages i.e. MISAPP, TRIP ALT, EST WIND and distance.
Anytime in flight, we fill RTE 2 let's say with the return leg.
Systematically , our ALTERNATE DESTS data will revert to DIRECT.
Did anyone noticed this?

[ImbracableCrunk]

How many airlines use that SOP? (ie Filling out the ALT DEST on the ground)

Could you simply fill in the RTE2 first?

[Skyjob]

ALTERNATE DESTS was a feature which could be deactivated by customer airlines in previous versions of FMC already.

RTE1 & RTE2 is a new capability for FMC since U11.

ALTERNATE DESTS refers to the ACTIVE RTE.

Each time a new RTE is active, default settings for ALTN are DIRECT, supplementary data is to be loaded separately.

[flyby797]

@imbracablecrunk yes we could. Still just wondering why ALTN DEST reverts to DIRECT when RTE 2 is filed in.
@skyjob Maybe my post isn't clear enough. We just file in RTE 2 and not activating it.

[None]

I have seen this situation...after setting the missed approach distance and altitude, sometime later in the fight it reverts to direct. It doesn't happen on every flight, so I don't know what the connection is.

We are using U12.