The NBA announced he was fined for violating the protocols, "which among other things prohibit attending indoor social gatherings of 15 or more people or entering bars, lounges, clubs or similar establishments."
Houston lost on the road to the Miami Heat that night.
Tim MacMahon of ESPN reported last Wednesday that Porter visited a strip club with teammate Sterling Brown.
The latter was hospitalized following an assault during that visit, with the Rockets announcing he suffered facial lacerations from assailants whom he "had no prior knowledge of or interaction with."
Brown is expected to fully recover.
Marc Stein of the New York Times noted Brown will not be fined and that the NBA's investigation into Houston's stay in Miami was closed barring new information.
Porter missed three games following the violation and returned for Tuesday's loss to the Minnesota Timberwolves, finishing with 10 points, five assists and four rebounds.
Houston acquired the USC product in a January trade with the Cleveland Cavaliers, and he is averaging 15.2 points, 6.2 assists and 3.8 rebounds a night this season. The 2019 first-round pick has shown flashes of his potential at times even on a Rockets squad that has the worst record in the NBA at 15-47.
The Rockets return to the court Thursday when they host the Milwaukee Bucks.