Trundle ult vs Tahm shield passive. (GAMEPLAY)

I was playing in a 1v1 tournament for 400$. I was playing Tahm vs Trundle. Trundles ulted with me having some Grey Health from passive and it gave him close to 1300-1400 hp from it. Now doing the math I was sitting at about 3.4k hp. Normally he should only get about 600 from the activate or somewhere around there. I think the game somehow read my grey health as extra health and sapped it based on that. Which resulted in me losing the fight and then the game. I am contacting the people who ran it, pvpro, to see if they keep the replays or somehow and if they do and I can find it I will link it. UPDATE. They do not keep them and I did not record it myself. Look into it please and thank you.