After changing a rich text block to use a different style (from a data table) it will ignore the material applied to the the default text style and it will use the color instead.
Result: The Play in Editor session defaults the color of the text back to using color instead of the material after the text style has been changed
Expected: The default Text style would use the material apply to it in the data table
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-76338 in the post.