UDistributionFloat member resets to null upon Blueprint Compile

A UDistributionFloat property is reset to NULL when compiling a Blueprint sub-class of a C++ class that has a UDistributionFloat property.

1. Create a new blank C++ project
2. Add UDistributionFloat property to Game Mode Base class.
3. Create a Blueprint sub-class of the project's C++ game mode base.
4. Open Game Mode Blueprint in editor, and change the value of the UDistributionFloat property.
5. Compile & save the blueprint.

Results: UDistributionFloat property resets to None.

Expected: UDistributionFloat property to not reset to none.