Possible editor issue with terrain copy

So I have noticed that on the editor I used to be able to use terrain copy to copy and paste an entire map now I am limited to about a 40x40 inch square before I report this I want to make sure this is an actual bug and not an intentional change and if anyone else is seeing it hence this post.

Looks intentional but I think the limit should be removed - original didn’t have it so no idea why it would exist now.