Rubber banding at the beginning of games

[jam]

In about half my games over the past 2 days, I've experienced severe rubber banding for a minute at match start (after the pre-game lobby). For the next 30 seconds there's ~1000 ms of lag, even though it says my ping is 30ms in the bottom right corner.

Here's a few matches where it happened:
431053
431967
441970