Apologies for the double-post, but I have something more to report. Ground support fighters (GSFs) are bugged:
1. There's a bug relating to GSF's being destroyed by hostile fire but the event being reported as a "catastrophic failure" from maintenance. This is visible both when they're assigned to normal ground support and when dispatched on independent operations. Conversely AA attacks against GSFs that do
not destroy them are reported correctly in the combat log (see attached image; you still get a damage report for the fighter even though it was reported as a maint failure destruction event.)
2. Independent operations ("Search and Destroy" and "Flak Suppression") are completely non-functional. When fighters are ordered to conduct such operations on a system body (with and without a colony present, with and without friendly ground forces engaging present) the fighters will drop like flies from "catastrophic failures." I have actually seen an AA fire against fighter combat report generated ONCE, but this is not the norm. Then again, I also saw fighters on the system body with a "seek and destroy" mission get engaged by a 20CM railgun STO, which isn't supposed to happen... but only once. This is by far the worst bugged part; I find myself at a loss to detail all the weirdness I've seen while running tests.
Most significantly, they appear to conduct no attacks against hostile ground forces at all.3. GSFs providing ground support to ground formations seems to be working as intended.
4. The game throws a "Function #2047 : Object reference not set to an instance of an object" error when instant-designing Fighter Bombardment Pods (and ONLY fighter bombardment pods.) Probably insignificant but worth noting.
Due to the complexity of this I've taken the liberty of setting up a clean-sheet test game. The "Red Planet" moniker appears to have been taken the wrong way by some, as some dastardly Soviet Martians have been discovered on Mars. On a nearby asteroid you've been provided with some toys; a troop transport with ground formations that also have forward fire direction units (and a generous supply of spares in a separate detachment, with the formations generously equipped with FFDs so you needn't worry about counting as you click and drag,) and various fighters. The "weak fighters" are thinly armored but generously supplied with MSP and fuel, and already split into test and control groups to demonstrate that the catastrophic failures are definitely not from maint failure, but rather enemy action. The "tough fighters" are stronger and there's a group with both autocannon pods and bombardment pods for testing both. The Soviet Martians have ground forces, but their STO batteries are set to hold fire by default. Both parties are flagged hostile to the other.
I am aware that Steve doesn't maintain dev versions of older Aurora iterations and he strips out debug access before issuing release versions for good reasons, so he may have to recreate this in his 2.6 version to track down the issue, but maybe it will help anyway.

Both forum-searching and asking around on Discord indicate nobody was aware of these issues. I know nobody likes the micromanagement of setting up ground support, but unleashing a horde of cheap fighters to scour out STOs seems like a much more attractive alternative than bringing capital ships into horrible consequences range...