Appointments+ sets wrong time for appointments

When I hover over a specific time in the table of appointment times using using Appointments+, the correct time and date for that appointment slot are shown in the hover text. However, when I click on the time, the time that actually shows up in the booking form is offset by 5 hours. So, if I click on 11:00 a.m., the form asks me to fill in the fields for a 6:00 a.m. appointment. If I then log into the administrative dashboard and correct the time for a booked appointment, it shows up correctly as a blocked time on the calendar.

I have my time zone set correctly on both WordPress and in the .htaccess file on my server. What could cause this? It is causing problems for my clients, who all think they are booking at the wrong time.