With Flexible Netflow becoming more prominent in Cisco IOS Netflow Configurations, we are starting to see a common issue in configurations that causes a major issue with CA Network Flow Analysis.
If there are interfaces configured to use Flexible Netflow on a device, you absolutely can NOT have a Standard Netflow configuration set up as well as it will result in 2 separate Netflow flow streams being generated from the router. NFA will look at this as that the router is constantly rebooting and it will start to add thousands of bogus interfaces.
Assuming the router configuration issue was already resolved, you can proceed.
Use How to cleanup bogus interfaces in NFA without losing data for cleanup procedures that will not delete data.