this is a tricky one.
The rules state
"Spend the required number of HQ tokens out of your HQ reserve, temporarily placing those tokens on the combat card; at the end of the game turn, return these tokens into the common HQ token(s) pool, and discard the combat card onto the discard pile next to the combat card deck."
www.commandsandcolors.net/thegreatwar/th...24-combat-cards.html
So it depends when in Phase 5 the return of tokens takes place, and the drawing of new tokens from the Common Pool happens.
www.commandsandcolors.net/thegreatwar/th...e-5-end-of-turn.html
In reading Phase 5, it seems like any End of Turn activities can happen in any order, for instance the Improved Logistics Combat card can be played, and HQ token drawn.
So I'm inclined to think that the Combat card HQ tokens could be returned to Common Pool, and then drawn as an End of Turn action, but I agree it isn't clear.