Yes, I have been experiencing this for two months on a regular basis.- almost every time I log in there are new dates open, and I have had to decline guests because of this problem. I do have my availability window set to 3 months, but that doesn't seem to help anything. I reported it to Airbnb about 2 weeks ago, and have done everything they asked, but the problem has still not been corrected. More dates opened today, and two days ago. Now sending them screenshots each time it happens.