Reportedly solved by Rule not Running when Created from Project Template - #4 by Emily_Roman but does not seemed to be. Specifically, my rule checks whether an assignee is in a list of assignees on task creation and - if so - adds the task to another project. Additionally, the template uses project roles for assignment. When I create a project from the template and the project role is assigned to one of the assignees in the list of rule-triggering assignees, the rule does not run.