[NTG-context] definefallbackfamily and uppercasedoublestruck not working?

Hi! I use the Neo Euler which has no doublestruck characters. Maybe I use old code, but I really think that the following has worked before: %%% \definefontfamily [mainface] [rm] [TeX Gyre Pagella] \definefallbackfamily [mainface] [mm] [TeX Gyre Pagella Math][range=uppercasedoublestruck] \definefontfamily [mainface] [mm] [Neo Euler] \setupbodyfont[mainface,12pt] \starttext \startTEXpage[offset=3pt] Test: $\blackboard C$ or $\mathbb C$ \switchtobodyfont[pagella] Test: $\blackboard C$ or $\mathbb C$ \stopTEXpage \stoptex %%% I would expect doublestruck letters in the output on the first line. The resulting file, compiled with a fresh Standalone, is attached. Best regards, Mikael