3run,

check the manual and you'll see that using the 'vector function' only creates a temporary vector.
vec_lerp stores its result in the first parameter.
So you are storing your results in a temporary vector, NOT in the actual camera properties.
So your results with these commaands will be inconsistant.

What Beta project are you talking about? So I can see it in action...
(just post a link to your project thread please)