[Gameplay] Blitzcrank passive bug

This happened in a game last night when I was playing Blitzcrank, I do not own the chroma pack or any skins for Blitz and I have not been able to get someone to help me replicate this bug. The bug happened at an early-mid game teamfight. What happened with this bug is that for the rest of the game I had a shield for ~120 health on my health bar, but it did not impact gameplay. I think this was caused by an enemy champion killing me with 1 ability when I had my mana barrier up. I died many times after that, not a very good game on my part, and even when my passive popped it didn't go away. The shield didn't go away when I used the shield from Seraph's Embrace either. Has anyone else gotten this bug before?