Coworker annoyed at unused time on microwave, is it that serious?

So, I’ve been doing something my whole life and never ever batted an eye to it. I put in my food in the microwave and open the handle before it even ends. Don’t know why I do this but I guess because I’m a bit impatient or I overestimate how much time it takes to cook and just stop it there. I’ve never been told that it bothered anyone that a few seconds are left on a microwave ever in my whole life.

I’ve been working at my job for several months and out of no where one coworker decides to bring it up and asks, “Who is it that’s been leaving time on the microwave?” Two coworkers say it isn’t them so it leaves me. She jokes and says I need to stop it. So I never realized this was a pet peeve and have been trying hard to remember to clear the microwave.

One time today I forget and she goes, “Who left time in here??” And I say “Oops sorry. I’ve been trying to do better.” She jokes but is clearly annoyed and says “no you haven’t.”

Is it that serious??? We get along well but she’s a be diva and can get an attitude easily lol. But seriously….people have worse haves than me like her forgetting food in fridge for months or missing her trash in the bathroom and it being on the floor. I know this because she’s the only one that does her makeup in there. I think she’s starting to kinda resent me for it.