We did the Advanced Search several times and were unable to find any errors in the php error logs or Apache error logs.
I believe the issue is that the 1.10 version does not place any collaborator information in the ost_thread_entry table.
I was unable to attach the file that had images for the information below.
In the 1.9 versions it appears that the
Collaborator information was added as an internal note. This information was
searchable.
In the 1.10 version it appears that the
Collaborator information is not added as an internal note. This information is
not searchable.