I leave the notification on because sometimes it can be useful if I've been working for a while and have forgotten to get up, but it does mean I get the request very frequently when I am or have been standing, too.
I read on here that your arm has to be parallel to your body to register as a Stand credit, so if you've been standing up and working (in the kitchen, for example, or at a Stand Desk) where your arm is perpendicular to your body and/or bent at the elbow, it annoyingly doesn't register it as a Stand minute.
Irritating, but difficult to get around in terms of programming, because there's no way for it to know when you're standing otherwise. Altitude won't work if you live or work in a multi-level building, so unless they can improve its motion detection, this is probably the only way for it to really go.
All you can do is just roll your eyes when it happens and drop your arm straight to your side for a while. I've lost count of the amount of times I've had to do this while eating a meal I had just started after being standing up cooking for the previous forty minutes.