I can confirm it happens. My friend lives in Shanghai, he is about to come to U.S. to study, and we are looking for a trip to New York. The price he found on his end is always 1 day off from what I see, if we are looking for, say Friday from LA to New York lowest is $119, Saturday lowest is $159, on his end he will see Saturday lowest is $119 and Sunday lowest is $159. I've never seen any other airline booking engine having this bug. And it's a huge one. Hopefully AS figure something out and fix it ASAP.

And as suggestion for OP, you can consider taking it to small claims court. As much as I love AS, this is 100% their fault.