The person who remembers the misunderstanding is the only one listening for the repair. A sentence that sounds ordinary to everyone else registers with them as an acknowledgement, because they are the one holding the context that makes it meaningful. Apologies can be delivered and received in a channel nobody else can hear.

This is useful when a direct apology would be awkward or unwelcome. A small, unremarkable gesture aimed at the specific thing will land with the person it is for. And if you are the one waiting, be open to the possibility that it has already been offered in a form you were not expecting to count.