I am a Houdini Indie Steam version user.
I updated to the latest version of Houdini on Steam, and also updated the Houdini Engine.
In the Houdini Engine version 20.0.590, even when I set up collision_geo in Houdini, collisions are not generated in Unreal. I confirmed that it works fine when I rolled back to the previous version(20.0.506).

I seems to get the same problem with 590 ... need to check back 506 but on top of that I have no socket created ....

I can confirm that rolling back to 547 the collision and sockets are back ....

they add a split mesh feature and that seems to break a lot of stuff. they disabled it by default in 595.
In the Docs

Split Meshes
The latest versions of the plugin support multiple meshes on a single HDA output node. Since older versions of the plugin did not support this, there may be differences in behaviour when upgrading plugins. This feature can be disabled by unchecking “Split Mesh Support” in the HDA Component in Unreal, however the option to disable this feature will be removed in the near future.

Different meshes can be created by appending a unique identifier to the collision or lod group names. For example, rendered_collision_geo_A and rendererd_collision_geo_B will create two meshes. A group called lod_1_A will assign an LOD to the first mesh.

This feature is only available if the “Static Mesh Method” is set to “FMesh Description” and with unpacked primitives.

I am still experiencing this in 20.0.653 and Unreal 5.3.2. Stuff that used to work in a "collision_geo" group now doesn't have collision. If I change the group name to "rendered_collision_geo" it works, but is visible. Split Mesh Support is unchecked on the component.

I can also confirm going back to 20.0.506 and everything works again. I tried 547, but it was still not working.

I've reported the bug as they set the use complex as simple on the wrong mesh (the collision_geo) instead of the render mesh (main_geo) that have the collision geo assigned but since it's use simple or project settings the mesh does nothing. They broke other stuff with 590 ....