Ey! it is November 10 and it is not fixed yet... the same thing has happened to me. I made a trailing stop buy order: spend 950 Euro to buy XRP, trigger price=0.18441 Euro when the actual price was 0.17500 at the moment of the order.
 Now, In my Open orders I see it with trailing stop value = -6799.8 Euro, which is totally wrong.
 This is very disappointing... I had moved from Kraken to Bitstamp because Kraken was a total mess and unresponsive, and now I am finding similar problems in Bitstamp.
 The worst thing is they have not fixed the error after al these days (I mean at least since this thread was created)