Hi asan102, thank you for taking the time to report this bug!
I can't reproduce the issue in 1.3.17 (3). The tabs act as your desired behaviour, i.e. opening next to the parent, and when navigating back, they close and re-focus the parent tab.
Would you be able to get the latest build from the App Store (version 1.3.20 (6)) and try again?
Do you have any extensions installed that may intefere with tab management?
Thank you for your help in making Orion a better browser!