First, Artist's prerogative Gam.
Second, I can only come up with one idea; perhaps they were going to repair the tracks to get it moving under it's own power. That's a Panther in U.S. markings. That could really be useful.
I wouldn't doubt that someone decided they could use them for whatever came at them next. One could conceivably argue that the need never arose or that the higher-ups in charge wanted them for study when the need never presented itself.
I've certainly not come across any information in my studies that suggests we ever used those tanks for our own battles. But I will not pretend that I have every piece of information on this subject either. Without someone who was there, or had heard the story about what is going on in that picture, we can only guess.
So, back to the first comment; Artist's prerogative. lol