Hi Hans,

Thanks a lot for having fixed the issue I was reporting.

Unfortunately I found another issue related to placeformula and alignment in math mode. 
In the following example the use of \startalign in a \placeformula triggers a weird behavior in the sense that the following instance of \startformula gets also a number, even though one does not issue a \placeformula command. Moreover the number is placed incorrectly.
In the resulting PDF I am attaching, please look at the numbers (4) and (8) placed incorrectly (and they are not wanted neither…).
When one removes the \placeformula command, the result is correct.

Best regards: OK

%%% begin bug-placeformula-align.tex
\definemathalignment[Lgather][n=1,align=left]

\starttext

\setupformulas[location=left] 
\placeformula
\startformula
\startLgather
\NC a_{n} = O(1)\; \mbox{ and }\; u_{n} = O(1) \imply  a_{n} + \lambda u_{n} = O(1) \NR[eq:O-ev-1]
\NC a_{n} = O(1)\; \mbox{ and }\; u_{n} = O(1) \imply a_{n}u_{n} = O(1) \NR[eq:O-ev-2]
\NC a_{n} = o(u_{n})\; \mbox{ et }\; b_{n} = O(v_{n})  \imply a_{n}b_{n} = o(u_{n}v_{n}) \NR[+]
\stopLgather
\stopformula


\blank
\hairline
\blank

\startformula
\startalign[n=2,align=left]
\NC a_{n} := {n - 1 \over n},\qquad\qquad \NC x_{n} := {n^2 + 1 \over n^2}, \NR
\NC b_{n} := -1 , \NC y_{n} := -1. \NR
\stopalign
\stopformula 

\blank
\hairline
\blank

\setupformulas[location=right] 

\placeformula
\startformula
\startLgather
\NC a_{n} = O(1)\; \mbox{ and }\; u_{n} = O(1) \imply  a_{n} + \lambda u_{n} = O(1) \NR[eq:O-ev-1]
\NC a_{n} = O(1)\; \mbox{ and }\; u_{n} = O(1) \imply a_{n}u_{n} = O(1) \NR[eq:O-ev-2]
\NC a_{n} = o(u_{n})\; \mbox{ et }\; b_{n} = O(v_{n})  \imply a_{n}b_{n} = o(u_{n}v_{n}) \NR[+]
\stopLgather
\stopformula


\blank
\hairline
\blank

\startformula
\startalign[n=2,align=left]
\NC a_{n} := {n - 1 \over n},\qquad\qquad \NC x_{n} := {n^2 + 1 \over n^2}, \NR
\NC b_{n} := -1 , \NC y_{n} := -1. \NR
\stopalign
\stopformula 

\stoptext
%%% end bug-placeformula-align.tex