Regulation 79 defines the rules - nay, the principles! - for advertising design contests that are covered by Part 8. According to this Regulation, the contest notices (interesting terminology...) shall include the information contained in Part E of Annex V to Directive 2014/24/EU and be sent to publication in accordance with Regulation 51, that is the general rules for communication with the Official Journal.
In addition, contracting authorities are supposed ("shall") also send a result notice in accordance with Regulation 51 and in compliance with the requirements in Part F of Annex V to Directive 2014/24/EU. This requirement is excepted in specific case if the information would impede law enforcement or be contrary to the public interest, prejudice competition (Albert will like this one!) or prejudice the legitimate commercial interests of a public or private enterprise. I find it interesting that in the last exception no mention is made to economic operator but a more generic term of "enterprise" is used. In case any of the exceptions occur the contracting authority may decide to withhold the publication of the information and is not under the obligation of doing so.