[Gameplay] Ekko has just killed himself.

I was trying a different build in a Custom game against bots while something really weird happened. When I was checking the damage I would do to structures using Rapid Firecannon, I managed to deal damage to myself (!) with its passive. Here is what happened: close to the end of the match, almost all of my enemies' structures were down already and I wanted to check the damage I would do with Rapid Firecannon to an inhib. It had full charges, then I used Ekko's E then hit the inhib, dying after that. My health was fairly low due to the recent skirmish with bots and the damage was enough to kill me even though I thought you couldnt damage yourself. The damage was not dealt by minions. In the attached link I post my match history in which you can see an Ekko killing another Ekko while hovering your mouse over the last kill that happened in the match. Also check that there is only one and I played against bots. I got really confused about what happened and still I couldnt try to recreate this scenario, but I'll try it tomorrow just to check this bizarre event. As you can see, I play in the BR region. Any clarifications on what happened would be awesome and if this really happens to be a bug, I'd be really happy to know if I managed to help somehow. Sorry about my poor english and thank you in advance Cheers William