Thanks for your patience while I had this specific case reviewed.
This is neither a glitch nor an error: when working on the stock DARWINS, our quants found a specific case where a swing trading strategy trading on a specific manner was accruing more Ex than it should.
They had to introduce a minor fix in the calculation of the Ex score, which might have had a minor impact in certain cases where traders hold trades open in assets that do not trader 24/5 (commodities, certain indices, stocks, etc.).
In your specific case, @eyon, while the drop in the Ex score may have had an impact on your overall score, the main reason why your D-Score dropped was because of your decrease in your Pf score. As can be seen in the screenshot below, the impact of Pf in your score is higher than the impact of your Ex score.
I hope this proves helpful, please do let me know should you need further assistance.