I suppose it was not an error, but the spread.
When you go short, you open a position by selling at the Bid price, then you close the position by buying at the Ask price, usually Ask price is not showed in the chart, so you just see the Bid price in the chart, but you position is not going to be closed by the Bid price showed in the chart, your position is going to be closed by the Ask price hidden in the chart. The Ask price is the Bid price + the spread.
So if you say the chart showed you +37 pips, in case of 3 pips of spread, your position was at +34 pips of profit, therefore the TP in 35 pips could not be reached.
Just a possible explanation, hope it helps you.