Hello,
I ran into this issue as well. Applications would not install during OSD, but worked just fine when deploying to an existing OS.
The problem for me was in the boundary groups in the References tab -> Content location. I had only defined my primary site server as being Fast, but not my SQL which is running on another server.
Adding my SQL to the boundary group as a fast connection solved the problem.
Hope this helps.
Martin
Martin Bengtsson | Blog: www.imab.dk