buffer times not correct

I know this is a very belated reply (and really, Zoom? No support response?) but hopefully it can help you, or others who’ve stumbled upon your question with similar inquiries about buffer time weirdness.

I did a little experimenting, and it may have to do with the “More Options” setting for your scheduler. Since you have 15-minute buffers, you may want to adjust the “Show schedules in increments of” option to 15 minutes instead of the default 30 minutes. Since your availability begins at 11:00 AM and you have a 15 minute buffer, the next 30-minute increment puts the start time at 11:30.

I’m not sure why it thinks 2:30 is an acceptable last meeting, as that doesn’t allow for the 15-minute end buffer before the end of your availability.

Also note that with 15-minute increments, you’ll have more availability options; it should be something along the lines of:
11:15, 11:30, 11:45, 12:00, 12:15, 12:30, 12:45, 1:00, 1:15, 1:30, 1:45, 2:00, 2:15, and 2:30
(to get rid of that last one you might need to adjust your availability end to 2:45, effectively building in your own end-buffer prior to the end of your day)
It’s my understanding that, with these settings, if someone books a 12:30 appointment, the 12:00 and 12:15 appointments will disappear, along with the 12:45 and 1:00 appointments, as these would violate the buffer. I’m also not 100% clear on how buffer overlap works; if the start/end buffers are not allowed to overlap, the 11:45 and 1:15 appointments might also disappear (11:45 meeting would run to 12:15 and its end buffer would conflict with the 12:30 appointment’s start buffer; similarly the 12:30 appointment’s end buffer from 1:00-1:15 would conflict with the 1:15 appointment’s start buffer).

Since no one from Zoom seems to be bothered to respond, you might have to experiment with these settings on your own to figure out how the buffer overlap works.