The defense of my team performed poor too in the past 2 days or so; my team conceded 6 goals in 3 matches against weaker teams. The opposing attackers were passing through the defense and scoring past the GK way too easily. Defenders and GK had relatively bad ratings. Like you said, it is not normal. I have good defenders and goalkeepers; before those 'anomalies', my defenders and goalkeeper performed way better. It is as if something has changed lately.