When attempting to attune to Aevitas, one of the relays wants to be placed on the central altar, which obviously won't work. I think this is probably the problem:

sl1 = aevitas.addStar(15, 14);

15 and 14, rounded down, are both 7, which means they get assigned coordinate 0,0.

How about actually trying it before filing a bug report?
The altar itself is also a relay.

Proof that this will work with some array (Holorogium, as it happened)

Same array with Aevitas

From above, demonstrating that I filled everything.

The version is 1.2.3-beta, I had discovered Aevitas in the sky, and I verified with a telescope that it was visible that night.

I have a repeat of this problem in current FTB:Revelations

No, you don't. The altar is a relay.

I have placed eight of the relays at the positions indicated by the constellation paper in my offhand, with the ninthbeing the Altar

doesn't change that it's not related to this ticket. Go to the discord server, to the appropriate channel, someone there can assist if you can provide screenshots.

I haz teh dumbz, aevitas was not in the sky