Let's say that you have two open positions: one long and one short; the R/R is 1:2; the positions are open either side of the market (Buy entry order is above price, and Sell entry order is below it). If the price moved up first, hit your limit, and then moved down enough to trigger your Sell entry but without hitting the limit and moved back up to hit your stop, you would still be profitable, because your loss is half your profit.
If you keep getting triggered entries and never hit your net limit before price moves the opposite way, then it is not a case of binning the grid system but rather adjusting it to the behaviour of that currency at the close of each day (e.g. widening or shortening net limit, checking for spread fluctuations, etc.)
I am new to the grid system so it is not for me to speak with authority, but for ranging markets it can work, so let us see if anyone has positive thoughts about it.
Of course there is no holy grail, so it is down to the intelligence of the trader to see the changing environment and adapt the strategy. The only issue here is differentiating between being patient with your losing streaks and being blind to a clearly failing system: that, in the end, is only up to the account holder to determine. . . :21: