Master slide formatting not applying to question pool

Hi all,

I've got a strange issue. I've got two pre-existing question pools for a SCORM module. I've been able to change and apply a master slide to the one question pool but the other isn't taking at all.

The full story is: A subject matter expert developed a SCORM module on a trial verson of Captivate 8. I've created a new scorm module on our fully licenced version of Captivate 8 and have imported her question pools. I was able to reset the question pool formatting and applied the master slide. It was actually pretty easy.
Now when I try to do this to the other question pool this morning I'm unable to. It doesn't reset, it doesn't apply the custome background, or clear the formatting or replace objects like the submit button (it just creates another one). Am I missing something that I probably did yesterday? I've been using Captivate 8 for about a week now so I might have missed something obvious.

Thanks,

Steven