Game crashes *exactly* once per game at ~10 minute mark. [CRASH]

For the last two or three months, I've had the most infuriating bug. My League client crashes (with bugsplat) once every game. There are three weird aspects to these crashes:

1. Unrelated to performance: my computer runs much more graphically intense games just fine, and the bug doesn't go away when I drop graphics settings to minimum.

2. Consistent: the crash always occurs at about the 10 minute mark. The latest it's occurred has been ~12 minutes in. The earliest is at ~8.5 minutes in. This is the strangest thing about the bug to me: I notice that it almost always happens at about the same time as my first back to buy a big component (e.g. Lost Chapter), because it more often than not happens right before I was planning to recall, while I'm headed back to lane, or right after I get back to lane from the back.

3. Periodic: after I have one crash, I get crashes in all of my following games until I restart my computer. When I restart my computer, I stop having crashes for a seemingly random period of time. Sometimes it's one game without a crash, sometimes I can go multiple days before they start again. But after they've started, I get them every game until I restart my computer again.

This is incredibly frustrating, and has stymied my ability to lane properly since I give a free kill 20%–30% of the time this happens. The reason that the number is so low is because the server seems to realize I've disconnected almost immediately, and sends me back to nexus without any fuss. I can also reconnect after the crash just fine, and usually I've got the bugsplat report sent and I'm back in-game just before my champ reaches fountain. After that once-per-game crash, I never crash a second time.

I can reproduce this glitch more or less at will by starting a game of League, but I have no clue what actually causes it: I couldn't reproduce it on another computer, and haven't encountered anyone with the same problem. I've tried repairing my League client (several times) and updating my graphics drivers. No avail, although after I updated my graphics drivers it was a day and a half before I started having crashes again. Think that was just luck, though, seeing as my drivers have been up to date for the last week or so and I'm still getting once-per-game crashes.

I haven't played much Teamfight Tactics, but I've crashed two or three times in TFT at about the same time mark.

I don't get crashes when I use the Practice Tool.

I would really appreciate some help with this. This bug is killing my ability to enjoy the game, I love this game so much but I dread starting a match because I know the crash is coming, and I know it will ruin my laning experience. Please help.