re: maybe the comet is passing through the cloud and the reporter didn't get it.
This description seems more accurate:
Spitzer also captured images of comet Schwassmann-Wachmann 1, which orbits the sun outside Jupiter. This comet is known to have periodic outbursts, possibly caused by the build-up of internal gas pressure as the sun's heat slowly evaporates frozen material under the crust of the comet's nucleus.
From: Independent On Line
Official Spitzer telescope page. No mention of a (free floating/independent) huge cloud.