Convergence issue in Gaussian
Is not it just the case?


Looks like it is indeed not the case. I think the phrase OP quoted from the manual, which says that the optimization stops when 


  The Maximum Force and RMS Force are two orders of magnitude smaller
  than the thresholds shown, regardless of the values of the
  displacements.


can be interpreted a bit differently, but I guess that algoritmically it is implemented in a pretty simple way: the above mentioned quantities should be at least 100 times smaller that the corresponding thresholds. And this is not the case for the calculation under consideration: Maximum Force value (0.000005) is not 100 times smaller (but only 90) than the threshold (0.000450).