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This is not a typo. The localization team often chooses the older forms of words and expressions in order to make the game feel purposely old timey.

https://www.merriam-webster.com/word...r-thing-coming
Quote Originally Posted by Merriam-Webster Usage Notes re: "Another think/thing coming"
In summary: Another think coming is the older of the two, dating in use to the mid-19th century, and originated in British English. Another thing coming appears to have come about in American English several decades later, probably as a result of confusion regarding the original phrase. Another thing is the more recent turn of phrase and now is more common, though it is frequently criticized.
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Typo-in-quest-An-Unreasonable-Request
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