Let’s dare to make a final summary (that is meant to clarify also the confusion recently reported Regarding the issue of missing high-energy PKAs).
You uploaded again the same identical neutron spectrum I already used to produce my figure above with FLUKA (by taking TKHEAV(1) as the PKA kinetic energy).
This neutron spectrum is actually similar to the test PWR spectrum provided with SPECTRA-PKA, yielding through the latter the reference figure I linked above, which is consistent with the FLUKA one.
If with your neutron spectrum you obtain from SPECTRA-PKA the black curve of your plot above, there is a problem with your SPECTRA-PKA calculation, since it does not reproduce the expected SPECTRA-PKA reference figure.
I believe that this dismisses any fundamental problem in how neutron-induced recoils are being generated or recorded in FLUKA.