Using the latest preview release (CL 2179372), I opened one of my maps and noticed a lot of static meshes were out of place. It seems the latest version has messed up with the location of actors that are attached to other actors (the child actors are out of place, the parent actors are in their correct place).
Is this a bug (I should ignore this and wait for the next release), or have you changed how attachments work (I should fix those actors locations)?