Unlike a piston slapper, when you change your power settings on a turbine engine, there's a lot more going on than simply less fuel going into the combustion chamber....there's bleed valves opening/closing, variable inlet guide vanes repositioning, fuel, air and oil pressure changes (many of which are being used as 'muscle fluids' to move other components)....
So while the engine itself may be quite happy with the power change, it only takes one of the supporting actors to step out of line and your power change doesn't go as planned.
Case in point: the BA 777 that almost landed at LHR.