I and Q channels switching

Hey all,

I am currently sending a repeated waveform to the USRP transmitter
continuously with a period of 0’s between each period.

The problem is the that my I and Q channels switch every time the
signal goes to 0, even if it is only for a brief time.

What are some possible causes for this?

I know there was a problem last year where the I and Q channels might
randomly switch, but I thought it was taken care of and incorporated
into the release branch before I downloaded it.

Jason