Please provide the following when creating the Ticket:

Game Version number: 1.3.0.157
Modded?: No (Yes/No)
If modded, please list the mods:

Issue Description:
If you check the "Earlier Evaluation" check box on the LayerTaskDefend, the task will complete even if you haven't killed any attackers.

That is not suppose to work that way.

Earlier Evaluation - When enabled, it will can finish the task earlier than the countdown when all attackers are eliminated. Can be combined with Delayed Evaluation.