Hi,
This has to be the strangest issue that I have ever seen, but I think I know what is wrong now.
I was able to replicate the issue, by changing my time zone. It looks like there is something wrong with the datepicker script when generating the dates, it does not compensate for the time zone shifts. The reason it worked on Tor, because it hides your time zone, that’s when I realized it could be the issue. Thanks for the helps with this!
Let me try to fix this on my local environment, and I will make the modification on your server as well.