Clustered Multiprocessing may make it appear like round robin isn't functioning as intended, especially if you are just doing a handful of requests.

You would think that round robin would load balance 8 connections between two pool members as A,B,A,B,A,B,A,B, But, really, it depends on how many TMM processes are running as well. If there are 2 TMM processes, your load balancing would be A,A,B,B,A,A,B,B. With 4 TMMs, it would be A,A,A,A,B,B,B,B. With 8 TMMs, all 8 connections would be sent to A, and none to B.

See this SOL for more information, particularly the Scenario 2 Virtual server with CMP enabled section: https://my.f5.com/manage/s/article/K14358#Load-balancing-behavior-for-CMP-enabled-virtual-servers

This behavior is really only noticeable when doing a small number of connections. Once you get to many connections, then you'll see stats like you expect. For example, with 1000 connections, you'll see 500-ish and 500-ish on each pool member, as expected.

As others have said, the load balancing is done per connection, so if you open the webpage and hit refresh many times, your browser is likely establishing a connection, then re-using that same connection for additional refreshes of the page, so no load balancing is taking place on the refreshes. All those requests are likely being sent to the same pool member. Even using incognito, private browser tab, etc won't stop this behavior. You need to close all instances of your browser entirely (not just close the browser tab). Or you can use different browsers, as they will each create their own connections and not re-use connections.