Designer latest retail release (1.8.3.641) - Windows 10 Professional
Steps to reproduce
I open a rather large (memory intensive, hundreds of layers, groups with fx and gradients) document A3 sized (primary doc)
Note that this document has 6 added viewpoints
I zoom deep into a random area and make edits
I open a another rather large (memory intensive) document A3 sized (secondary doc)
Second document has no viewpoints set
I just open it - no edits or zooming - then I close the secondary document again
Expected
The primary document is visible exactly where I left it
Observed
The primary document switches to the first viewpoint in the list at 100% and is now far away from there I left it