I thought the ANP claimed they were not a legitimate party...

I thought the ANP claimed they were not a legitimate party because it was not their role to oversee Petrobras  sales processes.
I don't see that they are offering any opinion either way, on the bid process.

It also stated its passive illegitimacy, since the "applicant is not contesting any act of the Agency, whether omissive or commissive." And, in any case, the theme is not included in its field of action.
The ANP, upon entering the meritorious question, claims that it is its duty "to regulate only the manner in which Liquigás Distribuidora SA carries out the LPG distribution business and, in parallel, the manner in which Petroleo Brasileiro SA carries on activities within the oil industry , Gas and derivatives, provided that the minimum regulatory requirements imposed by means of ANP resolutions are met ", and it is not within their competence to syndicate the announced share transfer.