Is it really a retcon though? The order in question is literally the only thing Gaius ever directly says to Livia. His view of her was never clear until Werlyt, because the reality is they barely interacted in A Realm Reborn.
In my opinion interpreting the order as a booty call comes entirely from a lack of understanding military culture and people having their minds in the gutter.
... but I can't tell people what and what not to believe.