create some item. set interval to a large value, let's say some 10 minutes. save it, verify that it receives one value.
modify this item to retrieve data more often, let's say once every 10 seconds. nothing happens.
only when the previously configured period passes new interval kicks in, even disabling/enabling item does not force clearing of this period.

this is especially annoying if you have some item set to a large interval (like 2 weeks...) then suddenly need to check it every hour. there's probably a way to make this work as expected by editing the db, but that's a bit cumbersome

ideally, frontend would nuke previously scheduled check and force scheduling of a new one. failing that, disabling/enabling item should do it.