I caught two of the same bromon because I found them both on different tabs and now I can’t find any more bromons. I think it broke my game.
Nah its just that they spawn with a late spawn rate
ive caught 2 too
Oh no, sorry to hear that! 
Did the extension reset after this happened, leaving only the Burger-Turtle in your monster collection?
We’ll take note of this and try to come up with a solution to prevent such errors in the future.
Update: I just reproduced the capture of identical monsters on different tabs. And it doesn’t break the extension collection.
As far as I remember, we had a code to ensure that this did not break the monsters collection. Although there will only be one monster left, the unique one.
Next time you see a dublicate, just fight one and let the other one run away.
they multiplied and then teamed up to break your bromon