My relatively new bike (~300 miles) has within the last 50 miles or so been developing issues with the front shifting. My bike has stock Sram sx-5 shifters and a deore front derailleur. To move back up from the granny gear, I have to push the shifter the entire stroke, wait for it to return and then push a little more. Same issue moving from the middle to the big ring. Is this a cable stretch issue? I did make an initial adjustment very early on. If not, any ideas?