CC74 in MPE not working on my S6 keyboard

Am using my Linnstrument set to Vertical controlling CC74 to try it out on filter cutoff
(I read in the manual that this CC74 should effectively be hard-wired to the filter cut off)
Setting my Linnstrument vertical axis to CC1 effectively controls the S6 LFO2 amplitude so my problem is apparently not coming from the Linnstrument set-up
All other MPE expected feature work (polyphonic pitch bends, polyphonic AT)

am I missing something here ?

ah found my own solution alone : setting SHIFT TX/RX E to lit 2 (ie “receive CC”) solved the prb