IBKR computes wash sales in a manner that compares each distinct trade, down to the hour, minute and second on a gross basis rather than netting purchases vs. sales for a given day. As a result, if you repurchase a security after selling the same security at a loss, generating a wash sale, the initial sale will be reported as a wash sale even if closed that same day.
For clients actively purchasing and selling a particular security throughout the day, this may produce a higher number of wash sales from a reporting standpoint. However, any disallowed losses will be fully offset by an increase to the cost basis that is similarly recognized when the replacement trade is closed that same day.