What´s far more annoying for me is when I send 20 units somewhere and one or two of those units jump off the road or rail into a jungle hex and I don´t know why. Takes a month to get them out of there again.
This is probably not a problem with the follow command. Here's what normally happens.
You plot a unit to move to a destination some distance away. When you do this you have a clear path to the destination hex. A turn or two later an enemy unit moves into one of the hexes in your units path. So your unit no langer has a clear path by road to the objective. It looks for another route not obstructed by enemy units and follows this route. Often this leaves you in a mountain or woods hex.
A sneaky strategy for the allies is to move the base forces at Victoria pt and Tavoy one hex forward at the beginning of the game. Typically the Japanese player will plot several units to those locations and by moving forward one hex you will get to watch them all run into the woods. Yes of course this is gamey but it often happens by accident. Some players want to try to run the base force at Victoria pt to safty for example. Or maybe a player tries to push a brigade forward of Tavoy.
You should never plot units for long distance unless you are operating in a totally secure area. When you get close to enemy forces plot one hex at a time.