Hi k61152442,
If you recently deployed the Experience Cloud ID service, then that service sets an amcv_(org id) cookie instead. In that cookie if there was an s_vi value it translates that to an aid paramater (analytics ID) but the main parameter used by the service is the mid parameter which is the Marketing cloud ID. This identification replaces the old analytics s_vi identifier in Analytics. I've seen people use D=mid before but I'm not 100% sure if that works all the time to capture the mid value.
I hope that helps,
Seth