It is unknown how to replicate this, and it is confusing to certain players. A possible to execute certain actions to do this. But it just makes your level jump from what level you are currently at to a higher level. An example:
Level 1 → Level 54
It's hard to explain for many players. Fighting monsters and doing random things such as changing "armor" and such will then obtain the exploit unintentionally. It`s unknown if this exploit was patched in the recent versions. It happened during version 1.6.
It is unknown if it is fixed, but on the computer if you continuously minimize and maximize the tab sometimes the chests will show up twice (about 1/2 a second apart) and you get the rewards of both chest. This also works with spells(double spells). You could take advantage of this to get parts for a mission twice as fast but it is hard to do and sometimes doesn't work.
Double Daily Reset Rewards
Okay so there is many parts to this exploit but in reality it is very simple. Reset rewards include; bounties, daily reward bonuses, wheel spins, and some other ones to be found. Players can receive double the normal amount of these rewards by changing the time and/or date while the game is open.
For example, If I had gone to the Town Square in Lamplight Town and had just spun the Left Wheel and/or the Twilight Wheel I could spin the wheel again (but with different items on the spinner) even without membership. All you have to do is spin the wheel for today, set the date for sometime far in the future (so you don't accidentally decline the next days reward) and refresh the page, then when you log back in there will be another chance to spin and you still get the current-day reward. It is the same deal with members except you get 4 rewards instead of 2.
You can do this with daily rewards (the rewards you get at the beginning of the game that get better as you hold a streak), wheels in town square, and bounties.
Note: If you go out of the specific place you are in, say town square, and you walk out to another place in the same map, your date will be automatically set back to the current date.
(Simplified) By changing the date of your computer, phone, etc, farther in the future, and refresh your page, you can get double daily rewards.
You could take advantage of this to get more gold, or possibly items, but in total it does take up a lot of time, this is something you can try that works with (from my experience) Google Chrome, and is easy but can be not worth the time.
Infinite Wheel Prizes
Changing Time Settings on a Laptop to the exact next day can make you get infinite prizes, just keep changing the time forward and back.
Rarely, Fire can do more damage to Water monsters. This is a uncommon glitch.
Misplaced character bugPlayers can walk on blocked places such as walls while you can't. So they can go out of bounds (out of the map), and others.
Double Map Bug
Sometimes if logging on to your account on 2 different tabs you will find decorations from the first map overlaying the current map (however this is purely graphical).
If your computer/mobile device goes into sleep mode during an arena battle when you reopen your computer you will be stuck in it and lose 50 trophies.
Question Correct Bug?
(Simplified explanation) "You get 5 dollars a hour, if d is total dollars and h is hours then what is the equation?" (d = 5 * h) This question seems simple but you cannot say d = h * 5 even though d = h * 5 (Incorrect) is equal to d = 5 * h (Correct). It is unsure if this affects any other questions.
Player Card Bug
If you walk towards the Twilight Wheel in Lamplight Town before it's time to spin the wheel and pull up a Player Card before you get there, the Member Card will fuse with the Player Card.
World Map Bug
When logging into Prodigy and clicking "All Worlds", all the servers will appear full even though they aren't. I'm not sure what causes this to happen.