I’d like to confirm I too am getting similar issues.
When my website editor team are saving posts as drafts they are being booted to the home screen (the draft is saved, but they are kicked out of the admin panel). This does not happen for full site admins.
Another issue that seems related, is when a site editor uses ‘quick edit’ and saves a post, the front end of the website is actually loaded into the admin panel within the posts list table. (I was seeing our website preloader but used the inspection panel to remove it, I have attached a screenshot of the result) – as above it seems that a HTML page is being returned somewhere?
https://ibb.co/k6cxbCB
None of these issues happen for main site admins, only for our editing team.
This does not happen when I disable the popup builder plugin.
We are using the latest version of the plugin.