Pen tool glitch?

Hello;

While doing a design, I ran into this problem. Using the line tool I drew an object consisting of a series of black lines stroked at 1 pt Needing to draw a complex line, I switched to the pen tool.

The problem is that when I drew the path with the pen tool and stroked it, the 1pt stroke was double the width. This was consistent, in other words, no matter what the stroke weight was set to, it was doubled in comparison to the line tool's stroke(which was correct). So, in order to match the object drawn with my pen tool to the ones drawn with the line tool, I had to set the pen tools stroke weight to .5 pt; half that of the line tool.

I saved the design and started a new design. This behavior was no longer there and the pen tool and line tool's stroke weight now matched.

Any ideas?

Thanks