From your Settings click 'Manage your Availability Scheduler' to edit the availability schedule.

When adding your available times you must add together the Event Duration and any Buffers. In this example the total event duration is 40 minutes:

In this example the availability will show for Monday's as the available time is longer than 40 minutes, however on Tuesday the available time is only 30 minutes:

Example: Tuesday availability is not showing:

When the buffer time is removed the Event Duration is now only 30 minutes:

Meaning the Tuesday slots will now show:

You can either remove the buffers or increase the available time slots.