Stretch in Bind Off Row

I just completed the diamond galore pattern found on this website and noticed the cast on row has significantly more stretch than does the bind off row. If I had four hands and stretched each corner horizontally I would have a trapezoid with the cast on row being longest. I used a long tail cast on and the bind off demonstrated on this website.

Is this normal and/or is there a way to insure equal stretch?

This is normal. There’s a couple things you can do.

Sometimes a larger needle helps when doing the bind off. You can also cast on provisionally and bind off both ends so they are the same. It depends on the project whether this is a good way or not.

Or you can just do a different bind off. This one is a good one and makes it nice and stretchy. Don’t use a larger needle on this one.
Jeny’s Surprisingly Stretchy Bind Off