After 20 or more years of continuous commercial use, it's just possible that the swivel pin in the head of your Forfjord anchor may have started to wear.
Don't worry. You can repalce it!
This kit includes the pin, a lock, and a key to hold the assembly together. The pin goes through the shank inside the anchor's head. The "U" shaped lock slides into the head and presses against the pin to hold it in place. The "V" shaped, angled key is press-fit into the head of the anchor where it secures the lock, and is held in place by sockets in the flukes.
Tools you will need: Sledge hammer and a propane torch.
You'll have to cut the original key with a torch to remove it. Once the new pin and lock are inserted, the new key is hammered in with a sledge hammer. Some heating may be required.
Note that the replacement pin mechanism is not galvanized, so once it is installed, folks generally have their anchor re-galvanized. By this time, the anchor is probably ready for a new coating, anyway.