IBKR Forex conversion not initiated by me

Hi all, I was charged a small forex amount (USD.SGD) last night at 6pm which was a suprise to me when I received an email from IBKR today as a daily activity report. It appears to have converted a small balance of less than 1 dollar, and there is no commission fee.

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My base currency is USD and all holdings are in USD while funding is in SGD. Last trade was about a week ago.

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Is this normal for IBKR to convert any balance in our account, without us initiating?

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Thanks!

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