Well, if it were a software flaw, it would always happen in a very specific set of circumstances, and I that's not what you're describing. My colleague Nick wrote above, "Are you using the supplied power supply and a good connection ? If not, please do. If you are, take the unit back to the store and ask for a replacement." You are using the supplied power supply, and you said you've seen this problem at two different locations right? On stage and at your practice space? The reason that's important is we have heard of weird problems occurring which turned out to be due to venues with poor power supplies… So, you should probably take exchange your unit for a replacement.
