Hi Neil,
in this case you show here Houdini is loading the OCIO config that comes with Redshift. Redshift ships with its own ACES-based OCIO config, which is tailored to work with Redshifts color management (ACEScg render space, specific view or display names, etc).
I think the issue here is that this config does not necessarily match the naming conventions or structure that Houdini expects for its own OCIO settings. Even if both are "ACES" the exact display and view names might just not match. So my guess is that Houdini will report errors if definitions are missing or have slightly different namings.
I’m not entirely sure what your goal is, but in general I would not override Houdinis default OCIO config unless you must use one specific config for some reason.
// edit: I just noticed that my Houdini 21.0.596 and RS 2026.2.1 seems to use the same config that comes with houdini. I guess RS made a change to their OCIO implementation to use the profile houdini uses. I wasn't aware of that.