Amp pages refer to the accelerated mobile pages. It was developed by Google and it allows certain web contents to come first. There is also an algorithm that Google uses to allow certain web pages to come first in their list when you search for a topic. Although it may seem great, unfortunately, sometimes amp pages have a higher bounce rate even though they are being shown first to the user.
That may seem great, but a bounce rate is bad. This is because Google is not showing the user the most relevant pages according to the topic they are searching, but since it has these amp pages, it is only showing them those websites first. The user will click on them and quickly click off of them without searching on their sites.