3d dice with advantage rolls damage twice too

Hello everybody. I am going to run the LMoP module soon, and I am practicing with Roll20 before starting. I set the setting of my game with the "roll always with advantage" option, but when I did I saw that now Roll20 rolls the monsters' damage twice too with the 3d dice when I click on the monster's sheet attack. I cannot avoid it, so I tried to change again the options of my game to "NEVER roll with advantage". Well it doesn't work. I save the changes at the bottom of the page, the browser reloads the page, but the setting remains "Roll ALWAYS with advantage". I tried a lot of times. Any solutions? I run Roll20 on Firefox 54.0 64 bit and Windows 7.

The second damage die is in case of a critical hit, just ignore the second die, it won't show up in the output unless needed. The damage dice are not affected by the roll with advantage setting. They can be delayed if you choose to select "Auto roll damage" to off, then you would need to click on the attack name to roll damage manually.

@Drespar: In the "my setting" tab, inside the game, the lowest and only thing is the "QR code for tablet". There is no "apply default setting". Anyway, if I find that option you said, does it revert the whole module to default (deleting the PCSheets/Tokens/Maps I added)? @Ed S.: The auto damage is Turned Off, players have to click on the name of the attack they did after the 2d20 were rolled. But my issue is not with PCs, it is with NPCs and Monsters. If I open their sheets and click on their attacks, they roll 2d20 and double damage (even if only one is taken in account).

Giovanni S. said: But my issue is not with PCs, it is with NPCs and Monsters. If I open their sheets and click on their attacks, they roll 2d20 and double damage (even if only one is taken in account). You can change your Game's Character Sheet Default Settings to ensure that newly-created NPCs do not auto-roll damage. In the "my setting" tab, inside the game, the lowest and only thing is the "QR code for tablet". There is no "apply default setting". This button only appears after you have altered at least one Default Setting . Anyway, if I find that option you said, does it revert the whole module to default (deleting the PCSheets/Tokens/Maps I added)? No, nothing is deleted. See: Applying Setting Defaults to Existing Content In-Game