Well I think it really comes down to it that the person your exBPD friend was living with (the one whom she is now upset at) just said something and it upset your ex BPD friend. The pwBPD is so unpredictable that it does not take much for them to paint you black; and even likely maybe your friend did not say anything that a normal and healthy functionning individual would take such offense to as to say "go away for the weekend and think about your behaviour" however with a pwBPD, you are dealing with a small child like mind. I do not think these pwBPD mean to sabotage relationships purposefully per se, but given their low level functioning of the mind, they are very hypersensitive also to anything so anything could have set her off and of course, to not feel her own feelings of shame, etc. she could have projected that onto your friend. Also given the pwBPD often does not like to take responsibility for their actions (again... like a child), this is possibly another reason she has blamed your friend and told her to go away and examine her behaviour. It is easier for the pwBPD to tell someone else to examine their behaviour that turn inwards and tell that to themselves. Some more projection probably going on.
These pwBPD go from bf to bf or gf to gf and same with friends. They go from friend to friend and then they may recycle back and forth through them also.
Thanks for your insight - I guess I'm not really taking into account the 'child' aspect of her disorder and looking at it through my eyes.
In an argument she becomes very condescending, almost as though she is trying to secure the role of an adult chastizing a child - Perhaps this is an effort to affirm her adult mind even though the traits she is displaying are child like.
The longer the NC continues the less sad I become and the more angry I feel; and the more I read about BPD, the more I realise that our friendship really is dead in the water. Even if she did try and recycle me (which Ithink she probably will once something life altering happens to her), I have little to no interest in having her in my life. I was aware that her disorder has affected her life for many years and she would become increasingly self destructive, but now it seems she is on a 'seek & destroy' mission to create tension and relationship breakdowns with the very people she claims to have relied on for so many years. This situation is now far too toxic for me and I'm no longer prepared to be a part of this destructive cycle especially as it has taken a huge part of my heart away.