Stegmann received a red card for striking a player with his elbow at a ruck in the 69th minute, which was in breach of Law 10.4 (a), while Mbonambi received a yellow card in the 12th minute for charging into a ruck dangerously, which contravened Law 10.4 (h).
The players will appear at a SARU disciplinary hearing in Pretoria. Advocate Tokkie van Zyl has been appointed the judicial officer.
Western Province Under-21 flyhalf Robert du Preez and Xerox Golden Lions replacement lock Ramone Samuels were also cited following their Absa Under-21 competition fixture at Ellis Park on Saturday. Both players received yellow cards during the match.
Du Preez was cited for lifting a player in a tackle and dropping him the ground, which was in breach of Law 10.4 (j), while Samuels was cited for striking a player with his arm and shoulder on the ground without the ball, which contravened Law 10.4 (a).
Du Preez’s hearing will take place in Cape Town on Tuesday, with Advocate Donny Jacobs serving as the judicial officer, while Samuels’ hearing will precede Stegmann and Mbonambi’s appearances in Pretoria.