HFSS interpolating sweep problem

See the attached HFSS file. Apparently, S11 and S12 have artificial resonace around 1GHZ due to interpolation. This can be verified by sweeping using discrete type. does anyone have good idea how to solve the problem?

Can someone address the problem? for wide band sweep, the interpolation doesnt seem right all the time.

What's the convergence? 1%?
and set more point for interpolating

Try changing the solution frequency, might help.:D

i saw 'interpolating' sweep missed resonate frequency for several times.
but i never saw it reported a false resonate freq.