7.6.6.3 Impress renders source file incorrectly

I have a three slide Impress file created under OpenOffice 7.3.7.2.

When I open it with 7.6.6.3 Impress it shows only the first slide.

Anyone have any experience with something like this?

Clearly the solution here is to spend more time with the problem before entry.
By changing the view, all three slides are proven present.

Great experience at getting into the help system but hopefully not a time waster for anyone else. My apologies.

Wish I could see a way to close this.

BTW it must be LibreOffice 7.3.7.2, the last one of Openoffice is 4.1