Mounting control board to heatsink

So I had to pull my control board off, and between the heat sink and the board is a piece of plastic. Is this supposed to be there? It seems like it would interfere with the heat transfer. Is this tape supposed to be there, or was it supposed to be removed (effectively there to keep the surface clean until the board is mounted)?

I believe that’s an electrical insulator / heat transfer pad w/ Kapton tape.

Yes, it should be there, please restore it to the original position if using the heat sink.