In the API documentation it says

ITE(A, B, C) evaluates and returns the result of B if A is true else it returns the result of C.

however it likely evaluates B even if A is false.

import sympy as sym
beta = sym.Symbol("beta")
expr = sym.ITE(sym.Abs(beta) > 0, 1/beta > 1, False)
expr.subs(beta, 0)

This yields TypeError: Invalid comparison of non-real zoo. We can manually evaluate each args but it means we cannot safely lambdify this expression. Seems like these lines are causing the problem.