Module isn't executed if parent has no definition for this schedule

Project P is parent of project M.

P has 1 build definition :
clean install - YET_ANOTHER_SCHEDULE

M has 2 build definitions :
clean install - DEFAULT_SCHEDULE (default build definition)
clean install - YET_ANOTHER_SCHEDULE

M won't be executed for DEFAULT_SCHEDULE

It seems that M requires P to be executed first - which won't happen for this schedule.