When editing in the back end, the view for our pages is defaulting to property view when a page is selected, published, etc.
I feel as though the default in our older projects was preview mode, but I'm not sure whether this is something that changed in v11, or if there's something I've missed that needs configured for that to happen.
Using Epi v11.9.4.
I believe you are refering to Sticky View Mode that was introduced in version 10+. Yes it's a new feature.
The way it works is that previously used view is loaded for the content authors instead of the default view.
There's a way to turn it off using UI Descriptors as described here: