The actual machining/ diecut was reversed...
Perhaps caught quickly and fixed so they could do a correct run?

Or was the machining done in a manner that allowed movement and it could flip randomly perhaps?

Am curious.... because my feeble little non-mechanical mind is trying to get a visual on the process.

and thank you for your response.

I admit, last night I pulled out all my generic/ inlaid binders and looked at them.
Mine are all normal... and couldn't recall ever seeing errors on these (sloppy centering a few times... poor edges maybe).

Thanks Don!
You are always a wealth of information.