Anything can happen but I would be shocked if ARC rings torqued to Ted's recommended specs are the issue.
Swapping the scope in question to another rifle proven to shoot, and swapping another scope to the rifle currently wearing the Leupold seems like a solid method to determine if the Leupold might be the culprit.
Swapping the scope in question to another rifle proven to shoot, and swapping another scope to the rifle currently wearing the Leupold seems like a solid method to determine if the Leupold might be the culprit.