I think GW2 switch the drink and water percentage.
In the description of “DRINK” it says that the percent reduced should be 10%, so if you have 10000 health and 10% of that is 1000, when you drink you should have 9000 of health but that is not happening, it reduces to 8001.
In the description of “WATER” it says that the percent reduced should be 20%, so if you have 10000 health and 20% of that is 2000, when you drink water your heath enhance 2000 health but its not happening, its enhancing 1000 of health.
Correct me if I’m wrong.