Probably a clerical error
Clerical errors are made by credit bureaus and creditors alike.
Since the card is not showing an all 3 reports, this rules out credit bureau error.
Probably the credit card company is reporting the card with some kind of error. It may be misspelling of your name, nickname, SSN, address, previous address or even your pre-marriage name.
These type off errors happen all the time. Factor in the merger issue – it must be it.
What I would do is call the credit card company and go over your details again.
If you manage to sort it out, do come back and share it with us..
Regards