Hi,
I have a strange problem with a (rather simple) Blueprint.
It appears different in the editor viewport than in PIE gameplay.
But first, here is what I did, piece by piece 
I created a Material Collection with a vector parameter, called “Tint”:
Then I created a material with a corresponding collection parameter:
Next, I created an Enumerator and a structure to hold a Group and a color value:
A blueprint holds an array of these entries and provides a lookup function to get the color, based on a group value:
In another BP, that holds a reference to the BP described above, the color value is looked up and applied:
That all works like a charm, but only in the editor viewports. Once in game, the color value is not applied:
So, in the editor viewports, the color that is stored in the datatable gets correctly applied, but in the game, it is not… 
Anyone an idea why that is?
What did I miss ? 