IRFs with wrong behavior

Hi, I’m trying to simulate a DSGE model with financial frictions, monetary and fiscal policies. When I run the script, dynare does not shows any warning or error message, but some of IRFs graphics make no sense. For example, a positive shock in the monetary policy rule, leads to a fall in the interest rate set by central bank. What could be the cause? Is it a calibration problem, or something worse?

I could by virtually anything. First, of course, you should check the parameterization. See [Monetary Shock)