New batch of ATR wrecks screen results?

At the beginning of last week, the flies in the optogenetics rescreen seemed to behave very different compared to all the weeks before: groups that kept the lights on now switched it off and vice versa. There was also some of that in the control flies, but to a lesser extent. This is what the last training PIs looked like for the seven groups before last week:

The data from last week then looked like this:

Especially the two groups that did receive ATR reversed their previous screen results. Potentially, reduced concentration of ATR may have reduced the effect of light which may have led to the reversal of the effects.