How do you feel about parent emails after hours?

I was having drinks with a teacher friend, and she was complaining about an email from a parent at 8pm on a Sunday. She thought it was inconsiderate and she couldn't even really help because she wasn't at her desk to look up what the parent was asking about the kid. I told her the parents probably weren't expecting an answer right away, and she was well within her rights to respond during normal business hours, but she was clearly tiffed about it. She is kinda a sensitive person, though.

The other day, my kid had a question about a project. My first thought was to email the teacher and ask, but it was 5:30 pm. I thought about what my friend said and didn't. I forgot about it the next day until my kid came home and wanted to work on the project! Kid had forgotten to ask too because they were busy with other things in class. So I scheduled an email for the next day at 8am and now 2 days are wasted.

So, what do you think? I didn't want the teacher to feel pressured to respond to a parent after hours especially because it was a simple question and I know everyone has email on their phones now. But also, I feel like society kinda recognizes that email is something that can be put off until its work time. Or is that just me?

ETA: In this case, I was emailing as a parent. Not teacher-to-teacher, as in, the kid was in my class and had a question about another class.