Way to diagnose why packet counts do not increment for a pool

So we have set up an iRule to route packets to a pool. There is also an associated Virtual Server. When we try accessing the endpoint with curl we see

SSLRead() return error -9806

Looking into the packet count stats, we see that the counts increment for the iRule, and the Virtual server, but not the pool.

What would be a good way to find out why the packet count is not incrementing for the pool ?