I was playing in my snapshot survival world, and I used a fishing rod with the enchantment set up:

Unbreaking 3

Luck of the Sea 3

Lure 3

Mending

Curse of Vanishing

When I attempted to fish in hopes of some neat loot, I executed the normal methods. I was not afk fishing, I was simply standing next to a naturally generated river, throwing the bobber into water that is over 2 blocks deep, even with salmon mobs in it. When the splash occurred, I right clicked, and my rod had a smoke effect in the water as if I pulled something out, but no item popped out. Even weirder, the bobber stayed in the water as if I had left clicked instead of right clicking. 

No durability was used. I tried using the rod on land and durability was used, but in the water there was no way to deplete it- I know it was a mending rod, but I tried it on a normal fishing rod too later with the same results. No fish, no treasure, no junk, no experience, no item damage. This worked fine yesterday before the new snapshot came out, so I know that this issue is recent. A friend of mine tested this as well and had a similar issue.

The world was created in 20w16a, but I created an additional world to test this glitch with this snapshot, and the same problem persists.