Taric Manaflow band bug?

I recently played a match against a Taric jungle, nothing new, seen it before, but what struck me as odd is that when he started attacking our tower at level 6 he was able to spam out his Heal quite literally for free, and I mean this as in his manaflow band was up the entire time he spammed it out 6-8 times in a row, so he could get free auto resets and speed, but it didn't use the band until about the 8th use of it. Can anyone confirm if this is a bug? Or did I just witness a hack on his Cooldown's/Mana use somehow?

Here's a link to the clip i highlighted of the first instance of it: https://youtu.be/J9mD-Qti0lM

I'd really appreciate any insight into this!

Edit: I reviewed the playback a few more times and noticed he literally got manaflow band 3 times and didn't use mana for 10-15 seconds while spamming abilities. I tried to re-enact it in practice tool with the same items and manaflow band but to no avail, so i don't know if he was actually cheating or if the bug has some sort of prerequisite conditions to activate.