I noticed something odd, this morning. I was going through my old problems, and I decided to change the topic of my first problem from "Classical Mechanics" to "Geometry." Then, I went to the community page to look for new challenges. However, I saw this:
The problem I had posted over 9 months ago was counted as "New!" That seemed odd, so I decided to do an official test or expiriment of sorts. I didn't know if this was a feature or bug, so this is why I am making a note. Tomorrow (9/28), I am going to change the problem's content; the next day (9/29), I am going to change the problem's topic. Each day, I am also going to take screenshots of how "new" the problem is.
The picture below shows the community page before and after the edit:
As you can see, nothing changed.
As I was reading through the comments, I read Ram Mohith's input on this; this phenomenon is definitely beneficial, giving old and dead problems a second chance; however, since editing the problem itself doesn't make it "new," I doubt this is an intentional feature. I feel that this phenomenon should be kept, but it should also be tweaked so that edited problems show up as new.
Once again, this is the community page before and after the topic change:
It was "new" again!
Brilliant user X X was correct, as suspected. I guess every experiment needs a conclusion, even though this doesn't count as a "real" and "rigorous" experiment:
In conclusion, there is a (suspected) bug with the community page algorithm that considers old problems with changed topics as new. The effects and intention behind the phenomenon can only be speculated about without official confirmation. However, this phenomenon can be built off of and learned from: Although this may spoil the Problems of the Week, this feature could be altered to make problems with edits made to the content considered as "new." Also, this phenomenon points out that the community page is not perfect; for instance, there is the bug where the preview for a problem starts an infinite loading process, and this loading preview covers some of the community content (see image below).