Siri sometimes updates old reminders instead of creating new
I've been noticing for quite some time that sometimes when I use "Hey Siri" to create a new reminder for later today, she ends up updating an existing reminder that I have instead. I can't seem to reproduce it now, but after asking her to create a new reminder she'll say "OK, I updated the reminder" (rather than "OK, I'll remind you"), and I see she's updated an existing reminder. Has anyone else seen this happen?
iPhone 5s, iOS 9.1