I received a response from Italki Support tonight. They had made some changes to the "Booked By You" calendar feature recently, which caused the issue. However as of tonight, it's working correctly again.

While I'm on the subject, though, and although I have no real hope of seeing these implemented, this is what I for one would like to see improved on the calendar:

1/ The ability to make a booking directly from the Check Availability display. Yes, it has a Book A Lesson button but that launches you back to specifying which type of lesson you want, and you THEN have to go back and reselect the date. This is boring, tedious and time wasting.

2/ The old bookings page had a drop down which let you jump directly to a week several weeks ahead to book a lesson. I'd love to see that back. I'd love to see a calendar picker even more. It would be better than having to click through several weeks, one at a time, click-click-click, every time you book a lesson a few weeks out.

3/ This is even worse when your lesson time zone is BELOW the bottom of the calendar, even on a huge monitor, and you have to scroll down for eeeeevvveeerrry single week to see whether there's a lesson available for that week. If you're in Australia and are booking lessons in Europe, there is usually a layer of lesson slots in the early morning our time, a huge gap representing our day and Europe's night, and then some lessons in our evening. Omitting any times where there is, say, more than a 2 hour gap either side would make this less painful.

4/ Since I'm dreaming the impossible dream, I'll go for broke and suggest a "One click" button to go to the last lesson that you have booked with that teacher.

5/ The ability to book multiple lessons rather than one at a time would be rather nice. (Recurring lessons don't always solve this.)

6/ Or if not that, returning us to the booking page instead of a page showing pending lessons.

I'd be curious to hear if any other students have thoughts about this.