Simple optical system aliasing, known behaviour or issue?

[Teusia]

Dear all,

I ran into a behaviour I would qualify as weird, but maybe I am just using poppy the wrong way.
If I use a large field of view and a small wavelength, it looks like there is some fun Fourier transform aliasing happening.

This is the code I used to produce the above PSF.

import poppy

pup = poppy.CircularAperture(radius = 39)

osys = poppy.OpticalSystem()

osys.add_pupil(pup)
osys.add_detector(pixelscale=0.001, fov_arcsec=2.0)

psf = osys.calc_psf(0.3e-6)

poppy.display_psf(psf)

I am using this build '1.0.4.dev5+g08d1eaa.d20220808' of poppy which according to git is the latest in the branch stable.

Is this an expected behaviour? or I did something wrong?
Best Regards,