Q:How should we interpret section 1.12.3 when it says “Remember that a charging unit that enters a zone of control must move into base contact with the nearest enemy whose zone of control has been entered”?

A:The intent of the rule is that if you enter a ZoC, then you must attempt to move into base contact with the nearest enemy unit whose ZoC you have entered. If you start a move in a ZoC, you can either move into contact with the closest enemy unit, or exit the ZoC by the shortest possible route.
If a unit does not have enough movement to make it into base contact it still moves as much as possible towards the closest unit. The intent of the rule is that you should not be able to charge through a ZoC to reach a unit further away but should always move towards the closest enemy unit even if you cannot make it into base contact.