Shouldn't do it in small big or big small. Do it yourself, its easy and satisfying when you have sorted it. It can only be cable tension or limit screw adjustment.
It shouldn't do it in any combination, if set up right, my 105 triple doesn't, in any combo, though you get chain noise in the large front, to larger rear, from around the middle of the cassette, on the middle with the trim I can use all gears, and inner certainly down to 14 (12-27 cassette), never tried 12-13 on the road.
To do the front FD,
1 make sure your on the inner ring,
2 release the cable at the FD, make sure your barrel adjuster is screwed in (should be anti clockwise),
3 put the RD on the largest cog, check distance of the FD cage from the inner ring and the the chain runs without contact,
4 pull front cable taught and clamp at FD adjust barrel adjuster to take up any further slack in the cable (just enough so the cage starts to move)
it should now shift from inner to middle or outer, if triple move to outer and check if still rubbing on outer you can adjust the barrel adjuster a little, but its likely to be the stop, adjust the stop screw and hold the cage with you other hand you will feel which way it goes.
