As mentioned in the title the new Display Entities "block_display", "item_display", and "text_display" all share the "glow_color_override" field; however, when trying to give the Glowing effect with commands to the entities the following error is issued:

"Unable to apply this effect (target is either immune to effects, or has something stronger)"

And changing the data for "glow_color_override" yields no change either.