I have run across this issue a few times. During a battle the opponent will repeat a non damaging attack, raising his stats or anything of like. this would make the battle extremely easy if they hadnt made it next to impossible to hit them first. biggest example the second member of the elite four. uses goldbat and doubbleteam over and over. so i rarely get a chance to hit him. then on the rare chances i do make contact he just uses full restore.