It's not just you. At very least it's us. Only needed to add 1 new reservation but it ask me to sign in repeatedly. I was afraid that my repeated attempts were going to cause all of my reservations to be lost. Finally got my ressie and all of my other reservations remained intact.
Yup, still messed up today. I'm afraid to change any of my current reservations in any form (either cancelling or adding) with the ADR system in such a state. I'm afraid the entire system will crash at just the right time to erase all of my ressies.