Dismissing a birthdate reminder error (Google Calendar)

Hi there! My Thunderbird is linked to my Google accounts. The google services that I use, and it`s linked to my Thunderbird - is calendar, email and contacts. As always, Thunderbird reminds me the events of the day, but some weeks ago, I started to receive reminders for birthday events, and when I try to dismiss it, I receive an error message. I noticed that only happens on birthday reminders! I think birthday reminders have a different behavior in google calendar, cause in my case, I use an option in google, that links my google contacts with birthday information in it, to the google calendar. So, every birthday event on my google calendar, is not created by me. It`s not even an event I can modify, cause it`s generated automaticaly by google, that as I sad, show google contacts recorded birthdays in google agenda automaticaly. I think the problem is that Thunderbird is trying to edit these kind of event, that I think it's not even an event! How to deal with it? Did I say something wrong? Thanks!