Form 3949-A is used to report intentional tax law violations. As you have amended and this was a mistake, the IRS will likely overlook any reporting.
For your daughter's mom, she can still claim your daughter. She can either wait to file until after your amended return has been processed, or she can proceed with paper filing by printing and mailing her return. Either method does delay her filing and processing of any refund. However, it does not preclude her from claiming your daughter and receiving any associated tax credits for the current tax year.
@mpellam12
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