[NTG-context] \start- \stopalign (in formulas) is broken

Hi, with the latest beta the following do not work anymore (example from math-ali.mkiv). \starttext \placeformula \startformula \startalign \NC a \EQ b \NR[+] \NC c \EQ d \NR \NC \EQ f \NR[for:demo-a-1] \NC \EQ g \NR[for:demo-a-2][a] \NC \EQ h \NR[for:demo-a-3][b] \NC \EQ i \NR \stopalign \stopformula \stoptext error: Missing number, treated as zero … Regards Andreas