Without an online reference to this, I am going to assume it's a random social media post making this claim, not an official post from the Observatory. I went to their Facebook page, they have been closed since COVID and have not posted anything since June 7, 2021.There is a observatory in Hard Labor Creek State Park. Just read that it may shut down bc of the lights from this monstrosity.
If you are really concerned, you have an opportunity influence this. Your town may or may not have a "Dark Skies" requirement in the zoning/building code. You *could* investigate this, and advocate adopting such an ordinance. You *could* contact Rivian and ask them to use "Dark Skies" lighting fixtures. You *could* join the International Dark Skies Association and educate Rivian about the importance of Dark Skies, and with their Mission Statement, it's likely that they would use (or maybe already are planning to use) Dark Sky approved lighting.
You *could* do all these things to influence the outcome, I've provided links to the resources above, but will you?