My front derailleur will only shift from small to big ring if I am in the 11 or 12 tooth cassette, and the derailleur then rubs on the outside of the chain. In the larger sprockets the front derailleur doesn’t move outward enough to allow the shift from small to big ring. I have installed new cables, happy with the derailleur alignment and height, L screw limit and there is plenty of cable tension (although have to fully unwind barrel adjuster for it to make the shift). I have tried to unscrew the H limit screw to move the derailleur outwards and give the chain more room, but this has no affect and does not move the derailleur (even fully unscrewed).
Anyone know what the issue might be or how to fix this?
edit: it is a Shimano ultegra FD-R8000, mechical.