Yes, there seems to be some limitation to the length of a formula. No one has reported an exact length limit but it may change depending on the formula layout. It has been mentioned before but most programmers either find an issue with their code or chnage the way they process the formula so I'm not exactly sure what the limitation is.
One known issue is that you have to make sure theres a space on either side of the operators - i.e. (~v1 = ~v2) and not (~v1=~v2).
Also, Check out this help file at
it has a great cMath reference with examples.