Red flag, is this a reason for concern?

I've been with my boyfriend for ten months. I have a fairly good relationship with his parents. It's his moms birthday today and they are holding a barbecue with the family and family friends.
However, I was excluded. Should I be concerned, is this a red flag?
1 mo
Just wanted to add more information, it was his family that excluded me.
It's not that I haven't been to any of the family gatherings with them and that's why I find this unusual, that on such an important occasion I am excluded when I have never been.
I have been given no reason whatsoever as to why I'm being excluded.
Red flag, is this a reason for concern?
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