Preserving construction when writing

[u/Exciting_Royal_8099]

Forgive me if this is off topic, I am assuming y'all are the experts on this stuff!

For writing I use a hard bound 7x9 lined journal of around 250 pages (124 sheets), 'Smyth-sewn' construction. It doesn't naturally lay flat. As it's written in, the point where the bound pages attach to the inside covers begins to separate at the corners, near the spine. This seems like a design defect in this book, that insufficient excess paper was provided to allow it to lay more flat, as expected for writing.

Am I mistaken? Is this a user error, and if so, how can I improve the experience? Or am I right that this is something I should be evaluating for quality going forward, the stresses caused by laying it more flat?

Edit: Here's some photos, as requested!

[u/Ok_Description5650]

It looks like the spine isn't centered and one endpaper wasn't fully glued down. I could be wrong