That doesn't sound right.
You should be able to use the right hand bar to select the correct segmentation to adjust.
You should also set an approval process such that you do not load copy until everyone is signed off.
I can adjust the copy when we are setting it up and getting everything together. The problem comes when we go for one final approval from stakeholders because the format could differ so a sentence needs to be fixed to remove an orphan word or something small. The goal is to have no changes but inevitably we do. I took a video of what I've tried doing and if there is a way that would be great. If not we will just have to deal with it or tell people not to make changes.