That is pretty surprising, as it would be in direct conflict to the
award terms on their website, I actually don't see any of that listed on the e-ticket just re-iteration of those same linked terms.
Some FT comments over the years (people appending reservations to add a leg, one guy even able to 'divorce' segments in 2018, etc) would suggest this to be a new change then or dependent on the communication channel (i.e. call center truly can't make changes, and can only cancel/redeposit/rebook)?