Strange ADR question

I just booked my ADRs for a party of 4. However, when I look at My Plans on MDE all reservations show as ‘party of 5’.

When I try modifying party and remove the ‘mystery’ guest from the list, MDE tells me ‘they have problem with connection’.

Did anyone else experience this? Or do I do something wrong? Or should I simply not worry about this?

Don’t worry. Likely a glitch. And even if it shows for 5, you won’t be charged unless no one turns up.