I was thinking of the "great commission" (Matthew 28:16-20), but that was not accepted. Googling for it, it is called "grande comissão". Is there a difference? I'll report it anyway.
No, you're right in reporting it. But "great comission", when you translate to portuguese, its closer to "terrific comission" (ótima comissão; formidável comissão). Nevertheless, isn't wrong in this context.
I first thought along the lines of an 'appointed body' while Lua_Amadeu seems to approve your last idea. The Reverso site supports these as the main meanings in Portuguese of 'comissão', so perhaps this has fewer possible meanings than our 'commission'?