Land was sent to one of my kd mates who has heavy tax on him but no acres were lost. I'm pasting the snippet of the messages they received as sent by the game.
have sent 696 explore pool acres (697 acres lost!) to Receiving Province (X:Y). It should arrive shortly! This aid shipment has added 696,500 gold coins to our aid surplus.
*a shipment of 696 explore pool acres (697 acres lost!) from Sending Province(X:Y). Trade deficit taxes cost us 41% of the shipment
As you can see, 41% tax is there but the entire acres was received. Is this by design or a bug which wasn't noticed before?
EDIT: Upon further checking, it seems the tax rate is increasing with each land aid being sent but the land aid itself is not getting taxed.