AG Radar Returns JF-17

With geeky HRM Maps from the Strike Eagle in mind, i was playing around a bit with the - at least from me- much neglected A/G Radar of the Jeff and did some small test setups.

As it turns out, some Vehicles seem not to have a Radar return.

Attached there are 2 Screenshots - The Setup and the best Picture i could get in DBS 2 - Zoomed in as much as possible.

Whilst 2 Command Centers, BMP3 and T80U give clear radar returns, a DSHK Pickup does not (okay, i can dig that. its small) nor does A Scud Launcher (thats the part i cant understand).

Is it supposed to be that way?