I've noticed a pair of Precursor ships that are much faster than the rest in my campaign: despite being 9500 tons, they have an observed speed of 8842 km/s, which is much greater than the 4150 or so the other precursor ships travel at. As soon as these two ships enter sensor range, they turn around and disappear entirely, hiding somewhere in the system. At first I thought they were spotters, but considering they don't get closer than my maximum sensor range (Which out ranges any precursor sensors I've encountered) before disappearing, I've a feeling they are meant to be high speed combat ships which refuse to pass the active sensor limit.
I suspect they are also the cause of occasional interrupts, causing only 3 - 4 days to pass instead of 5. I've had precursors get in amongst my civilian shipping lines before (Subsidies for everyone?) but these two seem to be darting around, avoiding my sensors and triggering interrupts on the civilian shipping without causing harm.
Is there any way apart from boarding I can find out what their components are? Or am I doomed to another decade of occasional interrupts while I research engine tech just to catch them?