The costume coordinator, if they are a prof, should not expect you to treat them as a professor on the show, they should expect you to treat them as a costume coordinator, and anything else will just hinder your growth as a stage manager
I am unsure what side you are coming down on this issue. In the high end, non-profit world, if I had let that happen, I would have gotten expected to get chewed out by the costume designer, the production manager and eventually general management.
But, as a stage manager, let's look at it from the bigger picture - and she is a professor - so she is not just dealing with the show (or shows) like a professional designer would in the world, she is dealing with course loads, advising, meetings, etc, etc . . . to waste her time is a BIG deal, especially with a failure to communicate. So, she should be treated as a costume coordinator with a very BUSY schedule - and I find nothing n the original post asking her to be treated as something else.
AND I don't think this is hindering anyone's growth as a stage manager - I think know the original poster will be more careful with email communication and learn to follow up with phone calls as needed with their a last minute or late schedule change. AND, realize that, in the end, being passive about something like this - like slipping a schedule change into rehearsal report, may not be as proactive and agressive in stage management as they want to be.
I don't think, in this case, it would be ideal to just put in the report, we are moving photo call - although it should have been in the report. The key players could have been notified separately about the cancelation, and then the conversation could have been started about WHEN photos could be rescheduled. What if the night in question was the ONLY night photos could have been taken (with professional designer's schedules . . . they are sometimes only one night.)
The other thing we DON'T know is this might have been a perfect storm of incidents, which required the tone of response. The reason to flag it to multiple people (especially the department head) is to make sure the line of communication is open. (In most cases, a professor is wise in dealing with such emails to email the department head so it doesn't turn into a he said/she said situation later.)
I think the issue of "wasting time" and "break down of communication" is being taken a little to lightly, this is a HUGE and costly situation. If my PR department hired a photographer to come in and shoot photos, and I forgot to tell them about the time change, then we just wasted three peoples night, a fee for the photographer, and perhaps missing a press deadline. We are also not aware of if this is the first such incident and the professor flew off the handle, or the end of several incidents.
I would be interested to see how the original poster had this all resolved and how it played out.