Two ways to fix the error and printing issue:
1. Detach the reference files and compress the file and re-attach the reference files for each model.
2. Add the logical name of the nested reference file containing the Shape for the Fence in the Print Style.
Taking this posting as offering an option of solving this by 1 or 2 (not both), Option 2 does not solve the specific problem I'm having. In my case, I'm seeing an error only for one file; the rest of my files present no issues. See my post here: communities.bentley.com/.../319455.
I am not keen to take Option 1 as I have several references that would need to be reclipped and reoriented, etc.