Viewport rendering zoomed in

I occasionally get this problem with some viewports/models in LO. When switching from raster to vector, the viewport zooms in slightly on the model, or the scaling is different. When opening the viewport to adjust the view it goes back to original scale, then zooms back in when closing the viewport. This doesn’t normally happen with most of my drawings and I can’t see how any of my settings are different to how I usually have them. Does anyone have any idea what might be going on?

I’ve attached a clip of what’s happening. First part shows the zooming, second part is normal operation.