In previous versions the actionbar title text doesn't have a shadow, in 22w24a this was changed and the text now has a shadow. This change was undocumented. The lack of shadow on the actionbar made creating and displaying custom HUD elements for custom maps simpler than the alternative options available. If the shadow is to persist, perhaps some way to display shadow rendering in json text elements similar to color, italic, bold, ect... would be a viable alternative.