Deformer Bugs?

I seem to have a major problem using deformers. I have it happen with bend derformers and lattices I know of for sure.

If I apply a lattice to just a cylinder for example (with subdivisions etc) and deform the lattice, then animate the cylinder moving across the screen (with the lattice parented so it follows), it doesn’t always evaluate fully on each frame.

For example, as I step through each frame, sometimes the cylinder is fully deformed by the lattice, other times, only partially. If it’s partially deformed, I can click on strength and sometimes that causes the evaluation to fully happen on the frame. Sometimes I have to change the strength value and set it back for the lattice to evaluate again.

What is the deal? Does anybody else have this happen?

What is the work around?