Photoshop applying incorrect stroke value to shape

Using Photoshop CC 2017. Trying to apply an inside stroke of 12 pixels to a 2400x2400 circle shape. I've done this with no problem many times before but for some reason today it's applying a 50-pixel stroke (I zoomed in and measured/counted). I'm thinking I must have accidentally reset something somewhere but can't for the life of me figure out what. Screenshot attached. Thanks for any help!