[Closed] drivetrain help shifting problem

I know, I know I should ask on a road forum but...

I've got a compact chainset and if I'm in the large chainring and changing to the smaller front ring, the chain seems to sit in between the front rings and doesn't jump down to the small ring. This only happens if the chainline is pulling towards the outside on the rear, in the smaller of the cogs on the back. Now I know I shouldn't be in small front, small rear combos but this does happen sometimes when changing the gears about.

Is this anything to with running 10 speed chain on 9 speed chainset?