Reverend Jueyuan and young Zhang Junbao
Was there any sign to them, or to others around them, that they possessed significant internal energy? Elsewhere in Jin Yong universe, ET-WYZ Xuzhu (having Energy Transferred from WuYaZi only; as opposed to ET-3XY: having Energy Transferred from all 3 XiaoYao Sect elders) was able to jump several yards high and break a wooden plank from a long distance immediately. Shi Potian broke everything he touched (including chairs and tables) right after his first freak accident. These were bona-fide signs of high internal energy.
Since Jueyuan and Zhang Junbao (about 20% of Jueyuan's power?) had tons of internal energy (which we know they did), they should have accidentally performed many extraordinary feats as well ----> example: if Zhang Junbao were to touch another SHaolin janitor, that janitor should practically die of electrocution (unless his kung fu was great).
And yet, nobody at Shaolin noticed these 2 powerhouses.