Random Final Defensive Fire

[El Pip (OP)]

I've got a squadron of four ships under missile attack.  Every 25 seconds a new wave of missiles are detected.  All the ships are of the same class, their beam weapons all have a 5 second recharge time and plenty of power and all the fire controls have the same setting of Final Defensive Fire.

What is confusing me is the inconsistency of their fire.  Against the first wave of missiles all the ships will fire, but then only two fire against the wave after, then all four will fire against the next wave, then three ships, then just one.  There's no obvious pattern to which fires and which doesn't.  It's not combat damage (the armour is dented but no internal damage on any of the ships) and they are all identical so I don't understand why some fire and others don't.

Is it a bug or this just something I have to allow for when designing my PD ships?

[MarcAFK]

It's possibly that there's some modifier based on initiative or grade bonus that's causing this, but I've never noticed anything like it.

[Paul M]

The only thing I can think of is the range to the firing ship may be changing.  Unless they are not seperated.  I'd think also your log file should have further information.  It should show what the ships chances were and the range to the missiles.  If there is no obvious problem shown by the log file I admit I'm baffled.

[Yonder]

You don't have auto-fire on do you? That can cause ships to make their own targets, which will remove them from availability for FDF. I think.

[El Pip (OP)]

Auto-fire is off, ships were all in the same location so the range wasn't changing, nothing unusual in the logs, each ship either fired perfectly normally or didn't fire at all.  They all have slightly different grades and so slightly different % to hit. 

I'm wondering if MarkAFK is correct and there is some grade/initiative modifier causing this.  I'm going to run a trial and see what happens.

[El Pip (OP)]

And of course now I cannot re-create it.

I've tried;
High initiative missile fleets against 0 initiative defenders and vice-versa. 
High crew grade launchers against untrained defenders and vice versa. 

In all cases everything worked just like you would expect.  The original incident involved a spoiler attacking ship, so there might be something unusual there.  Or it just takes a very precise combination of factors which rarely come up.