She's in love, somewhat possessive of Allen and can be a little aggressive about it. Doesn't that stem from their previous 'master-servant' relationship, which makes her feel entitled to Allen somehow? Also, her attachment may also come from imprinting her fondness for her late brother onto Allen, who also became her hero after that kidnapping incident eons ago. Don't forget that he was also instrumental in helping her cope with the loss of her brother and in devising how she can get her 'revenge'...
Put simply, her behavior might seem bizarre and even off-putting but given the context of how far they've come (together), it sort... of... makes... sense?