Quantum Mechanics and Relativity theories, have made obvious how peculiar the nature of time, leaving nothing but paradoxes left in some cases.
Opposite of this, the entirety of Calculus has built upon an assumed understanding of time, where an objects position at time t, is given by f(t), and it's velocity is dtdx​, the derivative of f(t) with respect to time, and the acceleration is the second derivative.
This forces us to treat time as continuous, with any given interval of time being divisible, whereas QM implies that time is quantized (or quantizable), creating conflict between the time of mathematics and physical theory (which relies on mathematics to get it's point across).