Slide rule cursor misaligned, how did happen?

[butforwales]

Hi Geoff,
Thank you for the reply! For me as a casual user, the item is actually in good shape, there is no blunt damages and the fittings are tight. It came with a worn leather case with the original owners name tag, address and phone number.
The problem is that when the '1' of C and D align, the 'π' of CF and DF don't. I can try to loose the two flat screws and hope there is enough play to realign them. But I feel like someone didn't know what they were doing. Wasn't that supposed to be precise instrument? And 1947 American quality?