In task reminder it is not possible to use variables in repeat attribute, because it is not parsed, e.g.:

<task assignee="${user}" g="224,236,193,52" name="myTask">
<reminder duedate="#

" template="my-mail-template" repeat="#

" />
<transition to="nextStep"/>
</task>
The solution here is to parse expression when timer (TimerImpl) is created
See patch attached.