ive come across incomplete CL often, but its usually with people stopping at the base cards and not following through with the rookies or whatever follows thereafter. Submitting an IR to correct it.
But for something like this, i've only came across a couple , but they were in the multisport section, where the product is put out and the mfr doesn't follow through with a CL. I know this subject was brought up sometime ago along with the use of the "TBA" or "TBD" in the card #.
Let's face it, if a CL hasn't been published, it can take a very long time to properly get it filled out. I had recommended before that maybe Admin can conditionally format the CL Name to a red color (or similar) or possibly placing an asterik * next to the set name to signify an incomplete set and required verification and/or completion.
Either way, it can be difficult as some cards may not be located for quite sometime or even identified on the list.