High content of potassium reported by spectrometer in silverware items
To give some numbers to MaxW's comment, you can see on this webpage the x-ray absorption energies of basically all the elements.

For example, the K-edge of potassium is $3.61~\mathrm{keV}$. The L-II edge of silver is $3.52~\mathrm{keV}$ and the L-1 edge of silver is $3.81~\mathrm{keV}$. So, it seems like you are somehow automatically assigning the peaks and scanning over a very large range of energies. The problem is that this will run into problems if you assume that all transitions are out the $1s$ orbitals (K-edge) because there are L-edge transitions for heavier elements which are comparable in energy to those from lighter elements.

So, without more information about how the transitions are being assigned, it seems very likely to me that MaxW was right to say these are L-edge transitions from Ag.