Queued tasks lead to chained events not triggering. Can tasks be prioritized?
QlikView's task queue system can interfere with task chaining events, as well as fixed scheduled tasks.
It is possible to configure the queue mechanism to allow for prioritized tasks. Review the possibility of setting up a Distribution Group / QDS Publisher Group, which allows for a more granual configuration of what tasks are run where, and how they are to be priortized against the queue system.