Ok, partially solved by cleaning out the patch to make a test for this post...
actually the "parameter on parent" dials are not updated which made me believe there was no change.
First I noted that if I directly assign a CC on the subobject on the parent patch, it works, even with the correct channel

So this is a cumbersome but working solution
Then I noted a discrepancy between the setting on the patch and the settings from the menu
Further exploration exposed that it actually works, but the dials on the parent are not updated. So I must have gotten the discrepancy problem combined with the dials not being updated which made me conclude it did not work. Still this sounds like a bug
Patch in attachment for verification
Thanks for helping out!
K
CCtestsub.axs (1.4 KB)
CCtest.axp (3.6 KB)