So as a preface, I do not really have an opinion about the hit box of Thresh's hook. That being said giving anecdotal evidence is not really proof of balance or lack thereof. As I understand this there could be two explanations for this happening.
One there actually is a disparity of hit-boxes with Twisted Fate, Thresh's hook, or both resulting in hooks landing when visuals would say they should not.
Two the game does not constantly calculate game state changes. While it does so at regular intervals (.25 seconds for most updates if memory serves) there are moments where game states are changing in between calculations. In these screen shots the hook is being thrown while the two champs are almost in melee range. This could also be a rare case of game state calculations deciding the hooks was landing at a calculation interval but movement occurred between calculations making the hook look like a miss.
Without more information on several factors that went into this picture it is hard to infer anything about the actually balance of Thresh's hook hit-box.