[GAMEPLAY] Karthus Ignite bug

Soooooooo I played a game as karthus to see the new reaper splah in the loading screen. While the game something strange happened: I walked to a bot with my E on, ignited him and then flashed away with my E still ON and OUT of the range, but the ignite didn't deal the normal amount of true damage. The bot got the ignite damage PLUS my E damage as magic damage and i repeat, i was out of range for my E to still deal damage. Tried it in two more botgames. It worked in two out of three times.

As mentioned before, I was Reaper Karthus. Picked with 12/18/0 masteries with Thunderlords as Keystonemastery.

Don't know if someone else experienced this bug, or if it only works on bots, but I would like to let the community know about this