I don’t have a minimal sample, but the following images display problems in linebreaks using LMTX (LuaTeX 2.07 20200920 + ConTeXt MkIV 2020.09.20 23:02).
I guess a sample would be required for a fix, but I have to find time to write it.
Maybe someone else could confirm a similar issue with linebreaks.
I enable expansion and protrusion, but the third sample shows unintended protrusion on the first line of the paragraph.
Also adding broad to hz and hanging in align doesn’t make any difference.
Many thanks for your help,
Pablo -- http://www.ousia.tk