my husbands ex which we've had horrible problems with ( she's tried lying saying she was talking to…

my husbands ex which we've had horrible problems with ( she's tried lying saying she was talking to him or that she was having his baby when he hasn't been back home for at least a year now she even made a fake twitter of him and numerous other things) just told me congratulations on instagram but I know for a fact she isn't following me. I have her blocked on Facebook and my instagram is locked.. is it wrong that I think this is weird and something isn't right with the picture? should also point out she hates me! and has never said anything nice to me what's so ever. am I wrong for feeling like that?