When they put out the description of Hakeema Bassey, she was described as 5'2", when it clearly showed on the monitor that she was 5'1"
After learning the sprayer was rigged to inject the operator, the agents assumed the person doing the spraying had been unknowingly injected. It's very plausible the person so doing could have intended to commit suicide after completing their mission (this happens with bombers and also mass shooters), so that was a faulty assumption.
Near the beginning when the agents respond to the scene, one of the agents asks if there is any idea what the victims ate. The victim directly in front of her was lying next to a partially eaten salad. While most law enforcement officers would call that a clue, the agent was oblivious as to what was right in front of her.