I don't know if this applies to you, but suspect it does. Folks have a tendency to set the tire/roller pressure too high.

That means that the tire gets a deep massage as it distorts coming over the roller. The correct load is just enough not to slip with normal riding. This means that there might be some slight slippage (squeak) if you suddenly accelerate. Various factors also come into play here. For instance, if the wheel has a bit of eccentricity, the roller has to be brought closer to prevent slippage as any low spot comes by. Also, consider friction; less friction, maybe because the roller is oily means you'll need much more pressure to keep it from slipping.

Years ago, I started winding very fine adhesive sandpaper onto the roller, and this mimics pavement, so I can ride with very low roller engagement force. I also modified the tension system with a spring, so the roller acts like a cam follower and is unaffected by slight wheel eccentricity.