Hi there,
Its literally as it says, it will run during upgrade. So the trigger won't be paused during an upgrade.
Regarding the case you are describing, that has nothing to do with this setting. That has to do with the mechanism behind this. When you use a time, a sys_trigger record will be created. Usually sys_trigger records are handled up to the second, or with a real minor delay. When there's a ton of processing happening and nodes are full, then this can take way more time like you are describing. If that happens often, do investigate whats going on on your instance.
