"Show end date" and "Repeat" checkboxes are confusing

Greetings! I'm attempting to use a date field with an end date and repeat options, but the UI has me very confused.

To add an end date (and repeat) I do the following:
1. The "Show end date" checkbox is clicked by default, even though the end date field is hidden. I /uncheck/ that to show the field - this seems to be the opposite behavior that the label implies.
2. I fill in an end date, but then must remember to re-check the "show end date" checkbox (which hides the end date) for it to save.

The repeat options also behave the same way. Unless I am missing something here, these checkboxes seem to be working in exactly the opposite way as their labels suggest. I've tested in both chrome and firefox.

Any help/advice would be greatly appreciated :)