Endurance score stuck

About a 1-2 weeks ago, my Endurance Score dropped significantly and has remained stable despite an increase in my exercise during that same period. I don't expect to see a significant increase in score as a result of my recent increase in exercise, but my Endurance Score is lower than its average for the last few months even though my volume is on average higher. It almost seems stuck. I'm running 18.14 and IIRC the update to this new software version seems to coincide generally with the change in my Endurance Score.