Unicode in a variable label

[Martyn Sherriff]

I am trying to use the Unicode 'combining overline' U0305 to indicate a mean value in a label:

label var x "`=ustrunescape("\u0394\u0305\u0045\u0305")'"
label var y "`=ustrunescape("\u00B5")'"

When I use these in a plot the code renders correctly, however when I try to display the variable labels x does not use the overline:

. display `"`:variable label x'"'
Δ̅E̅

. display `"`:variable label y'"'
µ

Is there a method to resolve this, or is just related to the graphical / text interfaces?

Thank you,
Martyn
Stata 15.1, Windows 10, Build 17672, 64bit