I have Aquaclears on my larger tanks in the fish room. Their motor tend to stick from time to time. When they do, I generally discover the issue a day later. At that point, the sponges have been sitting with stagnant water without oxygen. I 'm sure this has happened to everyone at some point.
Take a whiff. Smell like rotten eggs, right? I'd guess that it's due to sulfur dioxide, hydrogen sulfide and methane - the same stuff that builds up in deep anaerobic, dead substrate. Turning the filter back on dumps all this into the already stressed tank. While this will probably not "nuke" the tank, I can't imagine it to be a good thing.
No expert, but sounds like sound logic to me and worth taking a minute to tap out the sponge on the side of the sink.