Sounds like they didn't solve it. Instead, they delayed the latency so that it's in beat with the music 4 bars later or something.
The notes you play on your guitar don't come through until 4 bars later.
Which would make for an interesting sound experiment, but I kinda doubt you could you use it for serious jams.

I'm still waiting for real-life jams with video conferencing. Maybe someday, computer speeds will go through the roof and cable hookups get better compression so more data can get through.