Same thing has happened to me twice now. Except it wasn't in Tiltover's Finest Tactics (because RNG) - it happened both times while loading in ARAM.
Loading just sat at 100 %. I wasn't even aware something had crashed on my end, so I just kept on lifting while I waited for everyone to load. :/
At least the reconnect was fast (not using a toaster), but I was 3 minutes late to the party...
EDIT:
Video driver is 430.86 (EVGA GTX 1080), released May 2019.
And it just crashed again. When loading in ARAM.
EDIT 2:
Whatever was done, the bug's still there.
Seems consistent first game after switching from Tiltiover's Finest Tactics to any other queue.
...What was that about a separate client for TFT?