This user's project presents an Engine/Transient save error on certain Blueprints

This user's project presents an Engine/Transient save error on certain Blueprints. When saving the CharmState Blueprint, this message pops up:

Can't save ../../../../../UserProjects/jeffvoight_ciicharm/Content/Play/CharmState.uasset: Graph is linked to private object(s) in an external package.
External Object(s):
/Engine/Transient

The user states that saving specific assets in a specific order will bypass this save error.

The project can be found here as jeffvoight_ciicharm.rar :
\\epicgames.net\root\Contractors\Ben.Halliday

Reproduced in 4.7.3 (haven't been able to open the project in Main).

1. Download the user's project
2. Open Content/Play/CharmState
3. Save

Result:
Can't save ../../../../../UserProjects/jeffvoight_ciicharm/Content/Play/CharmState.uasset: Graph is linked to private object(s) in an external package.
External Object(s):
/Engine/Transient