Difference between surface current and current density?
Surface currents and current densities are caused by different effects, so they can be different. Here are some notes:
Current density at DC aligns with electric fields, but at higher frequencies it gets more complicated since time and spatially varying magnetic field also affects current density.
Surface currents are caused by discontinuities in the magnetic field between interfaces (see https://en.m.wikipedia.org/wiki/Interface_conditions_for_electromagnetic_fields).
That said, it's not obvious to me why they would point in different directions, just that it's possible they do since they are caused by different (and complicated) interactions between electric and magnetic fields inside and outside of the antenna.
Adding to that, patch antennas are &quot;weird&quot; in that the dipole or loop is not obvious because there's typically a grounded plane behind them with equal and opposite current, essentially cancelling out the magnetic field and making electric fields confined to the dielectric between the antenna and ground plane. The trick is that the edges have fringing fields that extend out into space that radiate (see https://www.antenna-theory.com/m/antennas/patches/antenna.php). Which, as a receiver, are the fields that couple to the antenna.
So I'm not totally sure of why it would happen in your case, but that there are reasons why it could happen.