The Prerequ section of DroidSentrySystemModule has a space after CounterMeasureModule which seemed to be causing the problem.
Original
...
<Prerequ>
<Techs>
<Option>DroneSentrySystems</Option>
</Techs>
<UpgradesFrom>CounterMeasureModule </UpgradesFrom>
</Prerequ>
Fix
...
<Prerequ>
<Techs>
<Option>DroneSentrySystems</Option>
</Techs>
<UpgradesFrom>CounterMeasureModule</UpgradesFrom>
</Prerequ>