Champion channelling spell bug

I was playing Zac and whenever I would use my E my ping would just sky-rocket, I thought it was my internet at first but I tested it in a custom game and it repeated 100% of the time I also tested it with some other champions and it did the same. I asked my friend to try the same and he got the same results. I made a video with 3 champions that I have tested, Zac, Vi and Varus. I hope this helps.