So long since I've looked at this but from memory, Dominic's original component was built were he had a drive that homed to index. When I first tried to use it, before the homecomp was devised by Dewey Garrett, we found it needed to set pos_fb = pos_cmd while internal homing to prevent following errors if using home switches attached to the drive. This was seperate to the homecomp but its still necessary.
In my homecomp, I have this comment
// RODW - the cia402 comp sets pos_fb = pos_cmd while internal homing to prevent following errors. This could be done here.
github.com/rodw-au/cia402_homecomp/blob/...2_homecomp.comp#L229
So not sure if its covered in Dominic's cia402.comp that you used as a base but I think it should be covered if this becomes an official comp in your ethercat repo.