Yeah Simple. The New Version Saving causes this from time to time
This is based on your original file location. Where was it created? Has your file been moved from another device/Not
Your saved Version backups Will look at that files current location and try to save any changes based upon that new file location. However this can sometimes send iWork into a downward spiral.
But MOST importantly Per Sjofors you might've created your original iwork file on a different version of Keynote/Pages/Numbers.
Solution to Troublesome files:
Create a new the file using whatever app it was created in. In other words eg. open keynote choose to create a new blank file. Copy across the slides/pages/charts etc. and paste into the newly copied file. Save and done.
then trash Keynote .plist file. Quit and reopen keynote
If this process is too long then take the following apporach but BE CAREFUL.
Navigate to all of your previous versions in your /.DocumentRevisions-V100 folder. They store your files in numbered folders basically the highest number is the most recent saved change. eg 66 or whatever.
Then think about what to do. next. If you don't know how to get this far in the second method then I wouldn't recommend doing the next step because Novice's will mess up their entire Mac playing around where they don't understand. Capiche.