[NTG-context] math mode underbar broken ?

Hi, I just came across this discrepancy: \starttext \startformula H_1 + H_A = f(\underbar{α}) \stopformula $ H_1 + H_A = f(\underbar{α}) $ \startformula H_1 + H_A = f(\overbar{α}) \stopformula $ H_1 + H_A = f(\overbar{α}) $ \stoptext Is this known or is under/overbar broken in display math mode? Steffen (2011.01.14 14:44 MKIV)