Because your code is so long and there has been cut-and-paste issues, as a check
Variables[Integrand]
results in
Are these the variables that you expect?
Crossposted here. As pointed out in the crosspost Integrand does not evaluate, it has unbalanced parenthesis.
Integrand
Thank you a lot for letting me notice the mistakes in copying my code in the question, now at least the Integrand should be ok!
