OK I think I see whats going on here.

If you look at this block, mined by BTC.COM here: https://btc.com/0000000000000000001bc14d31cd78cba9af69b4ef9af8fac9f3aabb260658de

You can see the size is over a Meg but the stripped size is under.

Same for the raw data for the last KanoPool block here: https://btc.com/0000000000000000001e04433a329abe9308ce304f64da81e8ec1c9d3522308b