Problem with MAX II EPM240T100

Hello people,

I tell you my serious problem

I have programmed a state machine in VHDL. This state machine works with an external clock´s pulses.

Simulation is OK.

When I see waveforms in oscilloscope, usually the MAX II works correctly but when one of the inputs change at the same time that clock (both slopes are at the same time) the output has an anormal state during one clock`s period.

I made the same test with the internal oscilator and I have the same problem.

I don´t know if this problem is normal or not.

Could be a problem of compilator of QuartusII?

Thank you very much!