Dear list, As I copyedited my book, I noticed examples where the underbraces in math formulas were not aligned vertically, especially toward the end of the book. Eventually I realized it was not due to my growing copyediting skill, and I have made the following minimal example showing the problem (I am using 2014.05.17 MkIV): \setupformulas[indentnext=auto, spacebefore=none, spaceafter=none] \starttext \dorecurse{3000}{ \placeformula\startformula \underbrace{\hbox{yyyy}}_{\rho} = \underbrace{\hbox{yyyy yyyy yyyy}}_{\rho} \stopformula } \stoptext It'll produce a 162-page file. On the formulas on page 1, the two underbraces in each equation are aligned. But there seems to be some kind of slow leak, because the underbraces become ever more misaligned. By page 162, they are visibly misaligned by maybe 3pt. If I increase the recursion count to 30000, on page 2129 the misalignment is about 30pt. Taking out the \placeformula makes the misalignment go away. I tried to reproduce the problem with plain LuaTeX, using the tex file below, but the underbraces came out aligned. \newcount\foo \foo=3000 \loop $$ \underbrace{\hbox{yyyy}}_{\rho} = \underbrace{\hbox{yyyy yyyy yyyy}}_{\rho} $$ \advance \foo -1 \ifnum \foo>0 \repeat \end Any thoughts on this very strange issue? -Sanjoy