If the chaff had maximum surface area-to-weight ratio approaching spiders ballooning, <2.5 um dust particles and dandelion seeds, and there were enough thermals

If the chaff had maximum surface area-to-weight ratio approaching spiders ballooning, <2.5 um dust particles and dandelion seeds, and there were enough thermals upwelling air in the area, it's entirely possible for chaff to persist as long as there is an average slight updraft gradient to periodically relift material. Granted, it's of limited military value unless it were dumped in large quantities (such as an/several E- prefixed US mil aircraft flying air defense suppression/Wild Weasel) and such upwelling wind conditions were present. It's usually intended to create false echoes to misdirect a missile or break a radar lock in real-time with a starting velocity similar to the original aircraft, and then it has no purpose once it separates far from the launching aircraft.