Some GRC files run with no errors but don't plot

[tom sutherland]

I have a simple grc file that shows the difference in Interpolation and 
Decimation using the Rational Re-sampler blocks. The program runs once, a "Time 
Sink" shows the signals(once) and then stops plotting and the Frequency Sink 
does not show a frequency plot at all. I've had other programs that do similar 
things, runs but nothing shows, once and freezes or for a few cycles and stops. 
Any thoughts on causes and /or how to solve/debug it would be appreciated. I am 
running GRC 3.10.5.0 on a Windows 10 Enterprise 12th Gen i7 machine with 32GB 
RAM. I've attached the grc/py and plot files.
Thanks...Tom

RationalResamplerInterpAndDecimation.grc
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RationalResamplerInterpAndDecimation.png
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RationalResamplerInterpAndDecimation.py
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