“A short-tracked Panzer IV. This was performed as a temporary fix when the suspension or track were badly damaged as it allowed the tank to either be driven or towed to safety where more extensive repairs could be made”.
That is actually shown in the US Army’s manual, going by illustrations in (off the top of my head) the old Verlinden Warmachines book on the tank.
There’s also a picture of an M981 FISTV in the 1991 Gulf War with its idler removed and the track put around the last road wheel. It’s in — I think — the Concord full-colour book on that war.
I suppose that explains the M53 Self Propelled Howitzer. Someone short tracked the prototype, no one told the guys in manufacturing, and they ran with it.