Incorrect date displayed

[putzhub]

Issue: When I select dates for availability it presents the wrong day of the week on the time selection.

Timezone: GMT-06:00 CST
Times: 6PM-9PM
Days: Monday through Thursday

My particular case: The circled dates should be Monday through Thursday, not Sunday through Wednesday. When I look at the calendar to edit the options, it correctly has the dates selected (Monday, Tuesday, Wednesday, Thursday, repeating over 3 weeks). But when presenting the options to fill in the day is shifted one early.

[putzhub]

Update: If I select "Central America" as the timezone, it displays correctly, but that's not actually my timezone (even if it does happen to be the same times).