How weird is this?!

ANHBUC - I agree she might be genuinely horrified - I wonder if this isn't mental probs, as she knows full well I have asked her not to - its as if she can't help herself. But even my bloke and best mate think she seems a bit, well, odd/dodgy.

Hi Rebecca, sorry you are going through this.  You might be on to something about the mental problems, I have an Uncle with Alzheimers so I know some people would not remember you telling them not to do something within 30 seconds.  It might be helpful if she has family that you might be able to enquire about her health.  Either that or try assessing if she has remembered other things you have told her recently.  Ask to borrow something from her but tell her you do not need it until tomorrow.  Then see if she remembers the next day. 

Wishing you loads of luck and keep us all posted.