I use custom user defined range bars (Renko). And Stop Loss such as ATR(10)*5 should normally set Stop at 5 times range of bar.
This is true at the beginning of the position, but then the stop changes aggressively to within few pips from current price... This happens before reaching trail value.
At times a position with 90 pips stop loss abruptly closes with just 3 - 5 pips loss after few minutes...

What could be causing it? Margin? Pipcost?

(Hedge set to '2', No Exit conditions hard coded in my script, No TakeProfit, Trail = ATR(10)*5)