My fishing rod currently has Mending, Lure III, Curse of Vanishing, Unbreaking III, and Luck of the Sea III in that order from top to bottom. For some reason, I think that Curse of Vanishing is causing the enchantments below it to be cancelled. I fished 30 times consecutively and I got fish all 30 times. I fished 10 more times consecutively and got the same results with the fish. Lure III was very obviously working as the fish were coming in every 3-4 seconds, the problem lied with the luck of the sea. According to the [Minecraft Wiki|,Luck of the Sea - Official Minecraft Wiki (fandom.com)] the chances of you getting a treasure with luck of the sea III is 11.3%, the chances of you getting a fish is 84.5%, and the chances of you getting junk is 4.2%. Now obviously that means that you'll get a whole lot more fish than treasure, but the fact is that out of 40 times I got ALL FISH? Curse of vanishing is not supposed to do anything other than make the item it is on to break upon death. I got a different fishing rod with lure II and luck of the sea II without the curse of vanishing for experimentation and fished 20 times consecutively. I got 3 treasure and one junk from that fishing rod. This might all be coincidental but this sort of thing has been happening ever since I got this fishing rod, I just didn't feel the need to count the results until now; quite plainly it just seems like luck of the sea is just not working with the curse.