One bad session does not mean anything definitive so I would be careful not to conclude too much from just this day. however, should this pattern continue and you decide to alter your program I would caution you to be careful about dropping too much intensity in your program (%1RM). In my experience, doing that while on a calorie cut only exacerabtes the loss of strength. Instead, if you feel the reduction in calories is affecting your progress and you still want to prioritize cutting, then I would recommend alternating days of cutting diet with your previous normal SS diet.