Expert advisors created with the strategy builder do not take incorrect trades. Hundreds of people use this software and we have a high quality code.
The ea takes the trades as per your trading logic. If you see odd trades, then you should review your logic.
In this case your logic seem fine but it's wrong. You are assuming that the signals are 0 (no signals) and signal (>0). In reality it works in a different way for your indicator.
I added this code to print out the indicator's value
Print("UP=",TrendUp[0]);
Print("Down=",TrendDown[1]);
It shows this:
2012.02.02 10:28:08 Symphonie_Trendline_Indikator EURUSD,H1: Down=1.3403
2012.02.02 10:28:08 Symphonie_Trendline_Indikator EURUSD,H1: UP=2147483647
So no signal is 2147483647 which in mt4 coding terms means empty. Your condition >0 won't work. You need to use <100000 (or any number lower than 2147483647)
This issue has been explained in the forum before in some links at
viewtopic.php?f=3&t=162I hope this helps. Happy forex trading!