That should have nothing to do with it. Seems like they just didn't know why the amex transfer bounced and tried to come up with a reason.
Recap:
Transferred points, saw it cancelled on Amex. Called Amex and did a new transfer over the phone which shows pending
Called BA SIN and got the BS about Visa, told the agent its BS so she came back you are right, it doesn't have to do with the visa but I don't know, not my dept, I can email and you will be notified in 7 days
Called Amex again, the front line told me it's pending & transferred me to MR which told me it can take 5 business days, its clear from our end bye
Called BA HKG, and again he can't tell me why it was rejected etc, he can raise an inquiry with my Amex conf number and the points will be credited in 72 hours
Called Amex and the agent tells me let me call BA - I see here (IIRC the link is down), she comes back that
BA doesn't want to talk with her because "Amex records its phone calls"