Henning Hraban Ramm schrieb am 14.04.2019 um 21:11:
Hi,
on the last page of my index, there are two entries printed over each other, see attached screenshot.

How can this happen? Any hints how to avoid it?

Sorry, no MWE yet, probably hard to reproduce...

Latest, i.e. yesterday’s beta with LuaTeX; the same with the previous version.
This can be a problem with the columns mechanism. You can try to disable balancing with

\setupindex[balance=no]

or disable columns for the index and flush the content within a columns environment.

\startmixedcolumns %[grid=no]
\placeindex[n=1]
\stopmixedcolumns
Also the same problem with lmtx, except that the text is garbage (I’m using Cambria.ttc).
Fonts in ttc format will work as expected in the next release.

Wolfgang