[2021] Was the De 7 Provincien just stealth nerfed?

We’re taking a look internally to see if something happened to Airstrikes. Thanks for pointing it out!

I believe that the additional seconds on the airstrike were unintentional - I cannot confirm this just yet.
People take days off on the weekends so Monday will be when I can learn something more.

I just tested it myself and I didn't see a bug.
The rear-most 105 won't fire over the top of the 150mm until the angle opens up more, but it WILL fire.
Looking at it, I don't believe it to be a bug, I believe it's just part of the firing angles of the secondary array.

I hear you - and I'm a huge fan of secondary ships myself.
Part of the secondary armament as a means of dealing damage still means opening up a bit to get as many tiny guns working as possible, just like the main battery. Each ship has it's own secondary turret angles and they don't always visually look like they're "trying their best" so to speak .
If you look at the GK - the main battery rear turrets visually look like they have a LOT more traversing they could do to open up the firing arcs, but part of the GK's balancing is the alpha strike throw weight balanced by the fact that it has to open up quite a bit and be vulnerable itself to get that alpha potential online. The GK is somewhat unique in that it has a badass turtleback to help soften that blow a bit when it chooses to do so.
So I suspect this is just part of the balancing, but I will keep it in my and see if perhaps it was an oversight.