Thanks for your reply. Yes, I do have water hammering enabled. I had it enabled from the beginning (2017) just thinking it was better to enable it than not, not necessarily because I had an issue. How did you solve the issue yourself, disabling it? The other option might be manually reducing the watering time for the zone which normally gets a little more because of this.
From your response, I looked up a little more and it seems you’re not the only one: Uneven flex watering - #15 by mjosephi