If you have 1 player injured for 1 day and the rest of the players in your infirmary are above 89% health the main Heal button at the bottom right will say to Heal 30. Which is 24 for the injury and 6 for the 30% Energy that player needs. If you push that Heal button it will take the 30 heal kits but only heal the injury. The player will still be at 70% energy so you waste those 6 heal kits. It works if you actually click on the player and heal them from there. Click Heal once for the 24 for the injury, then another time for the 6 for the 30% Energy.
Infirmary Heal Bug
I know this issue was raised a while back and sublinet / sweetnitro said they were aware of it, maybe they forgot to add it in the updates, here's hoping they'll have it sorted in the next one
I was told they will take care of it next week.