Getting married - MIL issues

So in only a few weeks my fiancé and I will be getting married. We decided a while ago we wanted to do something special to include all of our parents, as my mum is walking me down the aisle and my parents are divorced and remarried. So when I get to the end of the aisle we had decided for our celebrant to ask all of our parents if they give their blessing on our marriage and welcome the other person into their family. We told his mum about this a while ago. Today she decided to tell him she doesn’t want to say anything, that his dad can say it but not her… all they literally would have to say is ‘we do’

Would you take this as her pretty much saying she doesn’t bless the marriage or welcome me into the family?

I’ve had issues with her before but seems to have worked then out (I thought). My fiancé agrees that is does seem kind of rude and that it will look really rude on her behalf if she is the only parent out of 6 who doesn’t bless the marriage.

I’m just really triggered, we did this mostly for her so she could feel included in the day as there isn’t much of a role for the grooms parents.