Spierent TestCenter: TX rate under port counters is toggling between 0 and a different value.

When configuring a stream, if we specify the stream bps to 1000 then we are observing a TX "reset issue".  Basically TX rate under port counters is toggling between 0 and a different value, and looks like is "reseting" to cero. Once this counters is 0, this causes scripts to fail. Issue is not seen when bps is set to 2000.   

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