I think it would be a very useful addition to the game interface if there were an indication when a character won't gain XP for Energizing another character (or in other similar situations). I'm thinking something along the lines of what you see when a character is under the effect of Sorcerer's Might. Perhaps a little copper top battery next to the MP bar?
Generally this arises if a target has swapped MP with the energizer in the recent past. It is not always immediately obvious who has swapped MP with whom, especially if there is a lengthy message log to read through.
It can be extremely frustrating to send another character 30 MP only to find out it was worth 0 XP because the cool down has not yet expired. As a side note, I think the cool down period should be made known. It could be discovered by player experimentation, but that's asking players to discover an obfuscated game mechanic for no real reason (especially considering that Sorcerer's Might is broadcast to all and sundry).
Thank you for considering this suggestion!