Thank you very much for your detailed report. I can reproduce the issue here (along with the change fixing it) and will get it passed on to development.
I do like the new Reset Selection Box a lot. I just think resetting the rotational information should be permanent. Using it there is supposedly a reason to reset the rotational information of the element in its present state to zero. I’d argue that more often than not this reason doesn't go away after deselecting the element.
An example: I made a six sided square star which I use as part of a logo. I rotated it to 30 degrees so that it stands on one side. This is it’s final state. However, even if I convert the shape to curves it retains its initial rotational information so that everytime I select it I get a rotated bounding box. I find this distracting.
Now that there is a way to reset the box – why not make it stick?
