waveform simulation error

Apart from all confusion about unclear or non-existing error messages, I understand that you are referring to the different waveforms for signal F in post# 1 versus# 3 etc.

Unfortunately you don't show the design or test bench generating the waveform. I can just guess that it's a typical simulation to synthesis inconsistency problem, e.g. due to an incomplete sensitivity list. They are ignored in synthesis and respectively gate level simulation but required in functional simulation.

Please provide the complete code and we may understand the problem.