I´ve had the same problem. Some strips go complete blank, others show corrupted characters, others random pixel movement. I just opened a ticket a few minutes ago. It appears to be a software issue, cause when the strips work fine the resolution is perfect. Restarting the Helix can solve the problem, but not all the time, sometimes the problems comes back after a few minutes of restarting.
I live in Guatemala, so having a replacement could be a nightmare. I am crossing my fingers is a software issue that can be solved remotely.