Hi,
Shield tracks numerous core WP settings, such as your tagline (among other things). If your tagline is changing constantly, this is because you have a plugin/theme on there that is programmatically altering your tagline.
Why it’s doing that, is anyone’s guess, but something is doing it. But interestingly it’s not doing it for every WP load, only on some of them, which is why Shield detects it changing, constantly. You’ll want to find the source of the changes and determine why it’s doing that, and perhaps update the tagline of your site in your core WP Settings page to be the one you want.
To the question of compatibility, there’s no reason why Shield wouldn’t work with WP Optimise. As for running another security plugin alongside Shield, 1 security plugin doesn’t know what the other is doing, and we don’t support comparing 2x security plugins alongside each other. If you want to run 2, then you will need to take on the risk of that and potentially deal with any confusing or contradictory reports between the 2. We suggest you pick one and stick with that one.
Is there something you think is missing in Shield that you need from another plugin?
Thanks.