[CRASH] Crashing Upon Entering Nexus Blitz/Draft Pick Game

Over the past few days I've been experiencing client crashes. At first, I didn't mind it. I assumed it was a one time thing that would fix itself given a day or so. I play on Mac and have never had client problems before, besides occasional connection issues and a bit of lag upon selecting the store tab. The random crashing has gotten so bad now that I feel obligated to report it.

One or two days ago, I was playing Nexus Blitz with several friends of mine. Everything went smoothly up until we exited champion select and the loading screen launched, which is when my client crashed. Luckily, it fixed itself and I was in the loading screen before the game started and I didn't have any problems for the rest of the game. I played roughly two more games after that, with no problems, then logged off.

The next day I logged on to play more Nexus Blitz. I played two games, then on the third game I had another crash. This time during champion select. My client then tried to restart about three times. Each time, it would bring me to the login screen, and when I put in my login credentials the client would crash. It did this a few more times, now crashing as soon as the window showed up. This continued until I forced it to quit using task manager, restarted, and logged in. By the time I successfully did so champion select had ended and been dodged because I hadn't selected anything, and I had about a 3 minute wait timer when I queued back up with my friends.

Today I signed in and decided to play some Draft Pick. I queued up with only a little client lag, got into champion select, selected my champion and skin, and moved on to adjust my runes. Here I had a little client lag just before exiting champion select. Upon launching the loading screen, my client bugsplatted, then kicked me to the home screen without any way of getting back into the loading screen. The bugsplat refused to launch, and my client had told me that it had found some files that didn't match the current patch, and it started to update them. It didn't get far before my client froze and crashed, alongside the bugsplat. I re-launched the client, but couldn't sign in without it crashing again. I also still had the file mismatch notification from before. It then crashed twice, tried to re-install the legacy client, succeeded, and launched the legacy client only notify me that I needed to install the new client in order to play (the new client is still installed).

As of posting this, I haven't tried much beyond reporting the crashes. I hope that I won't get any serious penalties because of the bugsplat, since I have never gotten one and would prefer to never get one if I can help it, but if I end up having one then I won't make too much of a fuss about it. I will edit this after I try a few things and report the results.

Edit 1: Upon re-starting the client after waiting about 30 minutes, it immediately bugsplats.

Edit 2: I've been able to enter games now, after re-starting my computer several times and deleting some of my replay files. With the exception of one game, however, my client has bugsplatted immediately after a game ends.