Why did o get a cooldown

Today i just did one review that was dupplicated so i marked it as duplicate.
After that single review i got a cooldown warning. Why did this just happened to me? My last reviews were done a week or two ago without any problems.
“A cooldown has been activated.
We have detected some anomalies in your review behavior. Please ensure that you complete reviewing each nomination that is assigned to you. You will be eligible to resume reviewing nominations after approximately 24 hours.”
Answers
Was it actually a duplicate?
After just one? Weird, considering it happens when you review many wayspots quickly (they think you're a bot).
How fast did you review before doing this single one?
And this post it on the wrong sub, this is Misc Appeals, you should have created a bug report.