From my understanding, FBAR is meant to track how much money US citizens hold outside of the US.
Let's say that on June 2020 I had $10,000 (the minimum for FBAR reporting) in my account in the bank of London. Then in July 2020 I moved to Paris and transferred $10,000 to my account in the bank of Paris while closing my account in the bank of London.
I only had a total of $10,000 in my holding at any point in time. However, if I report the max amount of all of my accounts I would report
Bank of London: Account XXX: $10,000
Bank of Paris: Account YYY: $10,000
With an implied total of $20,000. Does that make sense? Could that come back to hurt me if the next year I only report $10,000?