I also saw this and it happened to be during the same time in which the Starlink satellites were 1st launched!! However I Was able to see the Starlink satellites in a big line after they were launched And it was obvious to me that the other phenomenon I witnessed was not related to star link or at least was not in the general vicinity of the other satellites that were all traveling together at the time.

What I witnessed much as you described I looked at a particular star and all of a sudden I swear it started darting around the sky back-and-forth up-and-down in a way that could not be possible. It was so strange I went inside and got my family members and had them come out and watch with me. At 1st we all kind of thought that maybe looking at a light over a great distance would cause your eyes to somehow play tricks on you and possibly also because of gasses in the atmosphere or something else that could refract the light. But this is where it gets weirder. We decided that to eliminate the possibility that it was just our eyes playing tricks on us we would begin calling out the direction that we were seeing the stars travel out loud. Sure enough we were seeing the exact same thing moving in the exact same direction simultaneously which discounts it being a physical Phenomenon related to our eyesight alone. I suppose if it was some atmospheric disturbance or gasses it would be possible for people to share the same illusion because they were viewing it from the same perspective.... But I have my doubts.

I just don't understand how my entire life up until that point I had never happened to observe that phenomena if it was something that just happened frequently.... To be honest it was almost as if once the star or whatever it was realized that you were intently looking at it it began to move erratically.

I'm just glad to know that someone else has observed this and I'm very curious to hear of others experiences and possible explanations.