Hi,
thank you Wolfgang (I just realized I only sent my thank you to you privately)!
Your threshold=20 solved that particular case. But look at the following example:
\definefontfeature[default][default][threshold=20,protrusion=quality,expansion=quality,lnum=yes,itlc=yes]
\setupalign[hz,hanging,line,height]
\definebodyfontenvironment[9bp][interlinespace=12bp]
\setupbodyfont[lucidaot,9bp]
\starttext
Gränsvärde föreligger i en inre punkt i definitionsmängden om och endast
om höger- och vänstergränsvärde existerar där och är lika.
\stoptext
I attach the output (latest lmtx). The word "endast" shows up as "endas t".
So, what does this threshold do? I can play with the 20. If I change it to 5 it looks better here (not perfect), but my document is approx. 250 pages, so, I fear it will break somewhere else...