they got removed from the tasks array, but not from the queue (for performance reasons). The queue gets cleaned up by the heartbeat, but it was checking if there were things in the main array, not in the queue.
There are a couple of other bugs with cancelling tasks that this doesn't fix that are rather more complicated to deal with.
This change breaks pretty much all API pertaining to synchronous task scheduling.
Significant changes:
- Server->getScheduler() has been removed
- Plugin->getScheduler() has been added - every plugin now has its own scheduler
- Because schedulers are now per-plugin, it is now unnecessary for PluginTask to exist because stopping plugin tasks on plugin disable is as simple as destroying the plugin's scheduler. Therefore PluginTask has now been removed and it is expected for things to now use the base Task class instead.
For the most part, plugins will simply need to change Plugin->getServer()->getScheduler()->... to Plugin->getScheduler()->...
Another highlight is that plugin tasks now no longer have global IDs - they are unique to each scheduler.
