Forgive me, I'm applying CW3/PF lag-finding tricks to a CW4 unit.
If it's taking 13s for 8s of in-game time to pass without the Relay, that seems very odd already, which is why I asked.
To narrow down the cause further, I'd suggest the traditional trick of starting from a blank slate and building a replica of the offending unit up, one step at a time, to see where the lag starts to occur.
I've seen a lot of odd tricks before, like a unit in CW3 which used the sniper-LOS check as part of energy calculations. So in any map with complex scripting, I try to have a blank map around to test the unit in isolation, to make sure that it and the game engine are the only possible explanations for whatever effect I'm seeing.
With that being said, there is another possibility. Talking to the GPU takes multiple milliseconds, and each frame only has about 32ms under ideal conditions before it starts causing lag. Half that, for anything visual. So it's possible that one of the animation-related commands you're using is causing the unit's mesh/texture/? to be pushed to the GPU. If that's happening each frame for half a dozen units, that could explain the lag. IIRC, colour-changes are probably safe, if the vertices only have attributes updated, rather than their existence being recalculated.
I hope some of that is of use to you. Good luck!