Suggested fix: don't draw tech dependency lines when they're outside of the current page (weapons/energy/hightech).
If there is a better place to report this (a modding bug), please let me know! Or if modding bugs aren't welcome, I guess I need to know that too.
This bug is only a display glitch, but I had to at least ask
EDIT: It is awfully useful when debugging to see a stray line... so it would be idea if the dependency could be specified in a way that made it explicit that the line should not be shown (use a negative ID, such as PARENTS ;-15, Y)