I think the reason she gave you is baloney.
"And I was uninvited bc she said my GROWN adult siblings aren't comfortable that I am in the midst of a nasty divorce and they don't want me and the negativity bc of the divorce there. "
I think it was HER that feels that way. I had a sister who is dishonest that way. When she wants to say something she thinks I'll take offense at, she always throws her husband under the bus: "Hubby said he doesn't want me to do that." It is in reality she herself who doesn't want to do it.