All of your examples yield the same output in which the numbers locate at the top and at the bottom of the integral sign.
I am looking for a way to place numbers at the right of the integral sign under the \startformula … \stopformula environment as the output of $\displaystyle\int_1^4 …$.
I am using the latest beta.
mtx-context | run 1: luatex --fmt="/Users/graph/ConTeXt/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/luatex/cont-en" --jobname="test" --lua="/Users/graph/ConTeXt/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/luatex/cont-en.lui" --no-parse-first-line --c:currentrun=1 --c:fulljobname="./test.tex" --c:input="./test.tex" --c:kindofrun=1 --c:maxnofruns=9 --c:purgeall "cont-yes.mkiv"
This is LuaTeX, Version 1.05.0 (TeX Live 2017)
system commands enabled.
open source > level 1, order 1, name '/Users/graph/ConTeXt/tex/texmf-context/tex/context/base/mkiv/cont-yes.mkiv'
system >
system > ConTeXt ver: 2018.02.09 00:04 MKIV beta fmt: 2018.2.11 int: english/english
system >
Thank you.