It is intentional. You will need two indexes, or creating your own indexing job. The default one will clear the content that was not found once it completes
@Quan, to we know the version number when this change happened and reason so we will know what to expect in case of custom job
I believe the behavior is not new, i.e. it is like that for a very long time. With your custom job you can get the descendants to index without clearing other indexes and that should be fine. However the better solution would be getting a new index
My client has 2 different sites in (2 different DBs, 2 different codes, 1 not multi-site setup),
We use to share 1 Find Index for both sites, running "EPiServer Find Content Indexing Job" use to index pages from both sites in 1 Find Index.
After upgrade of Site 2, running "EPiServer Find Content Indexing Job" from Site 2, Clear the find Index Completly and contains only pages from Site 2.
(running "EPiServer Find Content Indexing Job" from Site 1, still keeps pages/objects from both sites)
Wondering if this is a bug or intended change?
Site 1 versions:
Site 2 versions: