Hi,
You can remove that parameter by editing the php, that's not a problem. It it will result in the pagination looking exactly like when you have the simplified breacrumb setting activated.
All that setting does is that it adds or removes that parameter.
And that parameter is necessary for the breacrumb system to display in "non simplified mode".
Having that parameter in the URLs is not a problem for the SEO so if you want the breadcrumbs like that, I would recommend to keep the parameter in the URLs.