Always the same instance

I’m viewing a 2017 SketchUp model in 2018 Layout. Every new viewport I create changes all existing viewports to the same instance. I have a previous project with the same setup that worked fine. I could create new viewports each with a different scenes. I’ve checked all the settings between the previous project and the new one but the new one changes the scene in every viewport to the same one no matter what scene I select.
What could be causing this?
Thanks.

Most likely you’ve got the viewport on a layer that is shared across pages. If you want the content to be different on each page, it needs to be on an unshared layer in LayOut.

Here is the layer list for one of my templates. The layers indicated with the red arrows are ones that are shared so the same content shows on every page. I have a viewport select which is on the Model layer. That is indicated by the blue square to the left of the layer name.
Screenshot - 1_20_2021 , 8_07_59 PM

You can change the shared status of the layers by clicking on the icon to the right of the lock.