Quite possibly. Remember that the FS2 Shivans' first contact with humanity was with the NTC Trinity, not the GTC Vigilant.
Were we not talking about the 'seemingly Always Chaotic Evil/Omnicidal Manic' Shivans, we might be inclined to think that the sudden, 'unprovoked' attack by the original Rakshasa might have been because the NTC Trinity (possibly)attacked the Shivans first(out of surprise/panic at running into them), and without communicating, they have no way of telling NTF from Terran-GTVA.
Why would the Trinity attack? Both the Shivan-alliance concept and ETAK seem to have been top-secret and kept from most of the NTF. Furthermore, the NTC Trinity and Roemig had only defected "ten days ago" when the GTVA stumbled upon them. Roemig could have been a spy/informant prior to that, but still, it seems unlikely he'd be part of the upper echelon of the NTF. Odd that they'd pick such fresh recruits to power up the Knossos, though; perhaps it was because they were expendable?
The Shivans did try to set up a cruiser + containers supply depot by the Knossos, somewhat reminiscent of the fighter repair depot in 'Enter the Dragon', suggesting the Shivans were already planning ahead for an advance, though we can't know from that if they were planning to go beyond Capella.
The Ravana only made itself known by coming to the defense of the cruisers being attacked by the Actium and Lysander, and while it apparently mauled whatever capships we threw at it, it wasn't said to be headed for the node. We could explain that away as the Ravana being the command ship for the Shivans' Nebula battlegroup, and like the NTD Repulse, only to be committed to direct confrontation if absolutely necessary.
The first Sathanas generally only seemed interested in destroying things that got in its way, and the Tatenen which was (arguably) involved in the attack on a Shivan gas mining group. It then headed for the node rather than attack the GTVA destroyers in the Nebula, though that doesn't definitively say anything, either(deliberately ignoring them, or just leaving them, knowing another 80 Sathanes are en route?). It mauled the Phonecia, but that was a physical obstruction to where it was trying to go. In alternate briefings for High Noon(where there are still main beam cannons intact), the Sathanas also "obliterated the line of defense we had established to intercept it", upon reaching Capella. Sounds like they were directly in the way, as well. The second Sathanas seemed much the same.
After that, hard to say. The Colossus and mini-fleet's feint at the Capella-Gamma Draconis node drew a fairly mild response(IIRC, three cruisers and a few wings of fighters), until finally they sent the smallest thing they had that was capable of posing a threat to the Colossus: a Ravana. When that didn't convince the Colly to back off, they had to break a Sathanas off from "superjump" duty to finish things.
They then commenced "a massive attack at the Vega node", which was held off by "the majority of the [Allied] fleet". Cause and effect, or effect and cause? Were the remaining Shivans trying to push through into Vega, or was it a feint of their own? Alternately, was there a massive presence of Allied ships near the Capella-Vega node(knowing the Capella-Epsilon Pegasi node was about to be collapsed), leading the Shivans to believe they might be massing to pick up where the Colossus left off?
Interesting that no warships at all were sent to attack the Bastion at the Capella-Epsilon Pegasi node, only bombers.
