[CLIENT] [CRASH] Client randomly crashes in about 25% of lobbies

Most commonly in ranked, while clicking a champion during ban phase, but also while trying to select runes or reroll in ARAM, the client will immediately crash and restart itself (after showing a bugsplat window about 50% of the time).

This seems to occur only when clicking on things - I haven't had it happen when I wasn't trying to interact with a UI element.

This has been happening since last week, and occurs at least in 1 of every 4 lobbies - probably a bit more, but less than 1 in 3.