Hi Crispy24 (or others who can assist),
I have encountered the same problem with my parked domain not remaining in the browser bar for my WordPress site. You seem very experienced with this.
I’m going to be doing this a lot so it will be valuable to find a good solution.
Did you find a good solution for this?
I found the following link which partially explains the problem and offers some assistance.
https://www.ads-software.com/support/topic/domain-masking-038-wordpress?replies=7
It looks like WordPress does try to prevent this.
Thanks for any help you can provide.
Best wishes,
Mays