Bug has already been reported. This basically happens with any Houdini version later than 19.5.303.

Steps to reproduce:

1. Open the attached Unity project in Unity 2021.3 or later.
2. Open the scene "Assets/Scenes/SampleScene.unity".
3. Select the HDA instance named "terrain" in the Hierarchy windows (last object in the list).
4. Click the "Recook" button.

Expected behavior: Unity terrain gets passed down to Houdini Engine and HDA gets cooked.

Actual behaviour: Cooking fails and the following output is written to the console:

Unable to set `mask` height values on input heightfield node! Check your terrain sizes including Control Texture Resolution is less than the Heightmap Resolution.