Thank you for the really comprehensive and detailed reply - it's really helpful!
In what circumstances could Turbotax have entered a penalty in line 38 but NOT included a Form 2210? Because I have doublechecked and confirmed there is definitely not one.
It makes sense that the amount could be a penalty for underpayment of estimated taxes (I work for an international org where no taxes are withheld from my paycheck and my employer pays my estimated taxes and any additional due at the end of the year - but this doesn't change anything from the perspective of the IRS). My earnings can vary a bit from year to year.
I just want to know where TurboTax got the number from, and they won't tell me. Without a Form 2210, I don't know where it came from. I've now filed a 1040-x, but that penalty came from my first 1040. When determining the amount owed for my 1040-x, Turbo tax deducted [amount paid with my first 1040 - the $153 penalty], so it's essentially been carried over into my 1040-x. But that also doesn't have a Form 2210!
I'm sorry this is such a mystery to solve. Is it possible TurboTax just made a mistake and deleted my Form 2210?
