Adding Variable to Struct (Exposed on Spawn) breaks SpawnActor functionality without error/warning

Adding a variable to a Struct used with SpawnActor breaks functionality without warning.

Workaround: Clear Class from SpawnActor and reassign same class

User Cites Blueprint Compile manager as faulty.

https://answers.unrealengine.com/questions/817686/exposed-struct-at-spawn-doesnt-update-at-spawn-nod.html

Also confirmed in Main @ CL 4289943

4.19 Sample project Attached

1. Create a User Defined Struct, Set Variable type to string
2. Create an actor with struct var that prints string from struct on spawn (begin play)
3. Enable Expose on Spawn and Instance Editable
4. Create an actor to spawn actor with struct var and place in level
5. Make struct var in actor spawner editable
6. Select actor spawner instance in level and add some text
7. PIE -> Text will be printed
8. Add a new variable to your User Defined Struct
9. PIE Again

Result: In 4.19 String will print until you try to compile ActorSpawner and Actor spawner will fail to compile because of mis-matched structs. 

In 4.20 String will not print and no compile error will occur