While wielding a two-handed weapon (+50% Str bonus) with a low Strength such as to give a negative Attack modifier, the penalty actually increases (further penalty) instead of decreases (bonus.)
For example, a Str of 9 give a -.5 penalty to attack:

Instead of a 50% modifier from a two-handed weapon giving a bonus to -.25, it further increases the penalty to -.75:

In this case it doesn't change the final number either way, I just thought it was interesting to note. Not sure if it's intentional, but I kinda like it.