Razor Core X Question

I think I made a mistake. The last time I swapped out my RX 6800 XT for my RX Vega 56 in my Razor Core X, I saw the below piece of material and removed it. I don't remember seeing it before and it was slightly askew, so I thought it might have came off one of my video cards. While playing a game last night, it seemed the Razor Core X's case got super hot and I don't believe this is normal. Not sure if I am crazy or not, but I don't want damage the unit. Does anyone know what this piece of material is made of and how important it is? Also, does anyone know what I could replace it with?