@Welcome-To-SD0
In answer to your questions, I believe that
1. This has been happening since the Summer Release was rolled out in May. One could blame it on a glitchy algorithm but Brian Chesky has openly stated that part of the release was designed to drive people away from over saturated areas and suggest other locations, so that's one possible explanation.
2, 3, 5. That's how it's always been since I started hosting a few years ago. Nothing new there.
5. I don't know. It could be the recent updates. It could be something else. It could be a combination of the two. But, can I ask, how far out is your booking window normally, how far in advance do guests normally book your listings and (if you have not changed anything recently) has this always worked for you before? What are your reasons for having such a short booking window? I have found that most guests book at least a couple of months in advance.