I have exactly the same problem here. I did nothing except push the “Compile” button after updating. The problem appears with the PDF and Word outputs. I haven’t tried the others.
Also, every “Page break before” manually checked on individual text files don’t work anymore.
This issues has been addressed in Scrivener 1.5.6.0. Can you please check for Scrivener Update and test with the new version. Please, let us know if you still experience this problem.
@yblue82: can you specify your use case, as our tests show proper Page-Breaks when checked on individual files. It might be that we have missed your case of course. Feel free to send us a complete demo project with few example files that reproduce the problem, or describe your input files and compiled output result here.