When Jason opens up Talos's heel, it's the heel on Talos's left foot in all the long shots with visual effects involved. However on all the shots where Jason is interacting with a practical giant foot, it's of Talos's right foot.
When Hylas went back to pick up the spear Hercules dropped when running away from Talos the spear's position changed by about 90 degrees.
Around 00:36:31, the ship's stern is near the rocks in the sea, near the beach. Around 00:36:43, the ship is at sea, there is nothing around it. Around 00:36:45, the ship is near the beach and rocks again.
Hercules is shown on the beach setting out to search for Hylas, they cut to the ship and Hercules is missing from the beach.
Just before their fight with the skeletons, Jason and his two companions remove the leather straps they're wearing across their chests. In the immediately following close-ups of Jason, he's still wearing his.
The King and Queen of the Gods are given their Greek names, Zeus and Hera. The boxing champion of Jason's games is called by his Greek name, Polydeuces. But the mythical strongman who is one of the Argonauts, is called by his Roman name, Hercules. The Greek name for him was Heracles.
The name "TALOS" above the entrance to the treasure chamber is written in Latin letters. Whichever alphabet could be in use in those legendary times the Greek one would have been more likely.
When Talos attacks the Argo and picks the ship up by its prow, the ship stays intact while he shakes it from side to side. It is inconceivable that such a fragile wooden structure could have supported the entire weight of the ship. In fact Hera's headpiece falls off at the other end of the ship, when there is no reason for it to have done so.
Towards the end of the film Medea gets shot by an arrow. If you look closely you can see that no arrow is visible in the air, and that it would have to pass through Jason to actually hit her where it does, as he is in the way.
When Jason is being held in the Hydra's tail, he strikes the tail with his sword, but the sword bounces off the tail as if the tail is made of rubber.
When the harpies attack Phineas, the pillars behind them are visible through their wings.
When Zeus is speaking with his wife Hera regarding Jason, there is a female sitting in the background staring off to the side. But she periodically breaks character by looking straight ahead at the camera then quickly snaps back into character and resumes looking to the side.
As the first harpy appears to torment Phineas, the wire holding it up is visible.
When Talos is about to pick up the Argo there is a shot of the deck taken from the top of the mast and shadows indicating that the sun is shining from the direction of the bow. However, since the gigantic Talos is in front of the ship the whole deck should be in shadow.
After Jason's fight with Acastus, when Medea is telling Jason of the flower which can heal his wound, if you look past Medea you can see a mountain in the distance. On top of the mountain you can see a lighted building of some sort that appears to be a modern structure.
In the scene where Medea is performing, she turns around only to reveal her dress has an obvious zipper. Zippers weren't invented until the mid to late 1800s.
The various Greek temples visited by Jason, such as the oracle and the temple where Phineus is found, are shown completely in ruins, as they might appear today. Wouldn't these structures look new and complete in Jason's time?
As King Aeetes and his men watch the skeleton warriors emerge from the ground, Aeetes cries out as each one appears. But at one point, as a skeleton emerges, Aeetes is plainly seen mouthing something (probably "And still more!"), but his voice is not heard.
In two scenes with the Harpies, first when the first Harpy appears and the second when Jason and his troop come up the trail; the wires controlling the Harpies are visible.
When Pelias invites Jason into his camp, nobody present gives Pelias away as being who he is. Somebody would have addressed him by name, or his guards would have snapped to attention and perhaps saluted when he came into view. Nobody would have known that Pelias was concealing his identity from Jason.
Hera tells Jason that Talos' ankles are his vulnerable spots, but it was his heel that was his downfall.