CONF iture
You are totally right!
The system of voting a computer when the other two agree can have potentially lethal results, and therefore it should be indicated to the crew when this happens, so that some procedure allows us to make sure that the voting of a computer is correct. if computers alone cannot do it, get the pilot involved in the process. No reason to keep it "transparent to the pilot".
THe ECAM you suggest should be accompanied by an AOA CHECK PROC APPLY blue line, or something like that.