The defender was booked after team-mate Pontus Wernbloom appeared to tug the shirt of Sergio Aguero in the 77th minute of the UEFA Champions League clash.
City were awarded a free-kick but Wernbloom, who had already been booked, escaped punishment, with Ignashevich subsequently shown yellow.
A number of spectators questioned whether referee Tasos Sidiropoulos had confused the two players, but UEFA moved to clarify the situation on Thursday.
When contacted by Perform, the European governing body revealed Ignashevich had been penalised for dissent in the aftermath of the incident.
Seydou Doumbia scored both goals for CSKA, while City had Yaya Toure and Fernandinho sent off as they slumped to the bottom of Group E.
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