i can say like noiseless , it may be ur dc bais coponent
let me say how DC offset generated , and how it affect the ZIF receiver "zero IF"
when the lo leackage go from the mixer to the LNA , it attenuated due port to port isolation in LNA , and mixer , then it is go through the antenna
and received again , amplified by LNA , and now will be mixed in mixer with the same LO , so it will generate the DC offset , this appers in the ZIF receivers
1)
do you insert ac coupling cap preceded your switching stage in folded structure?
or just dc coupling? would you upload your circuit so that we can analyze it in
more detail.
2)
If the reason is because of the LO feedthrough, you can check the LO power at
LNA input to see how large it is? 720mV looks too large for me.