Just got back into coin roll hunting after a well-needed break and found this, any ideas? - Frittle :3
Is the line raised? Then it's most likely a "die crack". Since it appears to go from rim to rim, it's called a "Pre-Cud". Need better Pics please? Pre Cuds : Cuds on Coins (cuds-on-coins.com)
Here you go. The Die crack goes through the T and stops before it reaches the other edge of the coin.
I will try to find mine. I have one just the same. If it stops before touching the rim a second time it is just a die crack. The furthest progression that the crack touches the rim at both ends is considered a retained cud.
I would, too. It'll remind you to keep watching that area on these '71-Ds, as these have a way of growing.