Is there any indication that it is an issue that does need to be resolved, beyond knowing it’s been credited for your own piece of mind? When filing your joint tax return that claims the payment, will the IRS reconcile the total with the payments received in both person’s accounts? Or do they actually presume that only the primary on a joint return makes payments? I can see it being either way, unless someone has the experience of leaving the payments alone and filing without doing any sort of ‘fix’.
I imagine any payments that are lost in limbo dont remain there for long, unless the person making the payment forgets to include it on their tax return. It seems that at worst, the discrepency would cause the return to be flagged, requiring the issue be fixed before the return is processed.