I've just had this happen to me and Airbnb's response was to say it was down to my discounting.
There's a discount applied to stays of 7 nights or more, additional for one month.
I screenshotted 2 identical stays of 7 nights, with a €150 difference.
Some more excuses from Airbnb before finally acknowledging that there is a "problem" and asking for patience.
They recommended I set prices for every single night, which I tried doing last night, only for their system to override it overnight.
I charge 65 euros a night.
Some of these prices are going down to 43 euros a night, before length of stay discounts.
I am losing money here!