It turns out that deleting the headquarters causes immediate end of game as loser. Not surprising.
I am surprised about that. It was never like that.
The end of the game is when you loose all your warehouses (headquarter, ports, warehouses) or all military buildings (headquarters, sentries, towers, fortresses, etc.). So building up a warehouse and a sentry, then dismantling headquarters should not end the game. If so- it is a bug.
he said that he was building a warehouse. hence, if he delete the hq, he has no warehouses left, and he loses istantly