I was aware of this issue (when 2 rangers or 2 mages are both attacking from off-screen at the same time) and had it forcefully forget their cached positions ("Ranger forgotten", in the log). But it seems that didn't resolve it after all. I will look into it again
That isn't really how the script works. I'm not sure what happened in this case, but if you could provide screenshots of the simulations tab when it does, that would be helpful. The simulations tab contains evaluations for all available actions, including stepping closer to the mage. The information provided for each simulation include resulting danger, offence potential, travel distance, travel danger and prayer usage.
If you could screenshot the simulation that you think it should have picked (and the one that it did pick, which is at the top), I can make changes based on that. If you do, please click the simulation image for the relevant simulation to enlarge it.
Thanks