Bug with new item "Luden's Echo"

During our match, me (Leona) and MaeLucy (Hecarim) had over 250 MR. Doing the math between fiddlestick's 700 AP and Veigar's 1050 AP, We were melted in literally a split second each. Each of us having above 4000 health and even with their Magic pen, we should have at least lasted 5-10 seconds in the team fights. Please review the match for details if possible. The only factor that we noticed when doing our normal builds, was Luden's Echo. Normally when fighting Mages with over 800+ AP, we would usually last quite a while and be able to leave a fight towards the end. However, The fights we entered with both fiddlesticks and veigar seemed to have killed us within 1-2 seconds, both of use building complete tank.