GeoffR is kindly keeping a list of the current bugs in the first post of the Firmware 3.18.0 thread for everyone.

I have no issues myself on my H20 and for what it's worth no lock ups, but I've never had that issue personally. Mine is running smoothly with 3.18.0, I'm very pleased with it. It's so much snappier than the 3.15.0 that I was using previously.