Strange, non-ping, non-fps lag

Ever since I downloaded 7.24, I have encountered very strange lag that I have only ever previously encountered on the PBE. And when I say previously encountered, I mean it is the exact same type of lag. During the lag, my ping stays normal (61-70) and my fps stays 40-60. The lag begins rather simply, as the occasional lag between clicking on a minion and actually seeing damage dealt. Nothing major. Then, usually as soon as a teamfight begins, the game breaks entirely. And I do mean entirely. At the moment the fight starts, everyone on screen seems to freeze. At this point, I find myself either able to freely move my champion (but unable to interact with anything) or unable to move more than a few units before being rubberbanded back. After a few seconds, every other player will teleport to a new location, while I am stuck. By this time I have usually died, but my screen does not show it yet. After 20-ish seconds, I will see myself dead. Then for literally the rest of the game, everything is broken. I either move freely, unable to interact with anything, or am rubberbanded to a previous position (on my screen) constantly. It is worth noting that while I may see myself moving, I am sometimes just sitting in the fountain, which can be seen on the replay. Other players teleport around the Rift, or are frozen, or walk without interacting with each other. The chat works in realtime for short periods of time. When the game ends, I don't actually see it end, but rather I get a "reconnecting" bar on the screen, as though I disconnected regularly. At this point I have to press Esc -> Quit, as though leaving the game. Afterwards, I will reach the endgame lobby. Again, this "desync" is something I previously saw on the PBE, but when I tried to report it, the bug report would not submit. The last time this happened, my game recording software was not active, but I will be recording games in case it happens again and will post it here.