Very much like the $5000 books on Amazon where the algorithms are anticipating flipping an existing listing. Congrats on winning this round! The next step might be interesting which would be to go back and re-purchase the Condo once the price corrects to the 'real' price and bank the difference.
I have read this article and the one before it and it sounds very much like some folks who fell in love with their own idea and got early feedback that it was "working", went all in and never checked to see if it was still working.
The lesson should have been, "When you perturb an emergent system, never assume that the current state is the new steady state."
The most interesting thing for me back when I was in college was a discussion on of the professors on feedback systems gave on LA's freeway systems. There are three major interconnected freeways, 405, 110, and 10 which at the time formed a triangle. Now there is the 105 which cuts off the tip so perhaps a smaller triangle. The professor shared a paper that tracked "brake waves" which were aggressive braking maneuvers that would "propagate" backwards on crowded freeways. The paper showed that at the right time of day, an aggressive braking on any of these three segments could result in your own braking wave to "lap around" and hit you again. Sort of a ringing of the system.
This sort of effect can be present in any system that isn't centrally organized but is instead a result of the interactions within the system. Buying and selling real estate is such a system, especially when you are a 'market maker' in that system.
There are a lot of papers on how HFT trading algorithms interfere (both constructively and destructively) with each other on wall street exchanges. Just interesting stuff in my opinion.