I think our adult kids can be weird at times too.
We have three boys: Husband's who is 32 and engaged. Mine who is 31 and getting married July 27 and ours, he's 23 and the reason I'm here for those new to the board.
Anyway my stepson's fiancee has only been around 2 years. They met, moved in together and got engaged. She is a year older than him, never married and a very strong woman. He is on the quiet side. Her name is Jen.
They spent last Father's Day with HER family in Wisconsin (as they do ALL holidays) whatever! but he had a cookout for his dad/us during the week after Father's Day. Yes we were moving out of state soon so it would be our last one in Chicago for who knows how long. She also invited my son and his fiancee. Jen did not talk to any of us at all the entire time we were there. She was making her work lunch when we walked in and did not even look up or offer us a cold drink after an hour drive. He had done all the cooking as he is a trained chef. I was never so uncomfortable in my life or felt so unwelcome. My son's fiancee (Julia) later said the same thing. It was horrible. I felt sorry for my stepson also.
A little background was that a dinner before that with the six of us at our home, my husband drank too much wine and was kind of an ass but not anything terrible. In fact I even asked my son and his fiancee if they were offended and they said no. My husband has a strong personality also.
So I was very angry and confused after we left the cookout. We talked about it in the car and really had no idea what was going on. That following weekend JEN texted us saying they were near our house having martinis and did we want to join them. HUH WHAT??? We were just at the house and she was the rudest person I ever met. I was on my way to a wedding shower so husband responded no that I wasn't home blah blah.
Long story short, next time she was back to normal and friendly. I left it alone. MY SON was like get over it, forget about it, one thing and you hold onto it forever!!!
What I'm saying is that I could not believe how my son acted over me wondering what happened. So it goes under the rug and we'll never bring it up again I guess.
Moral of story: you are not alone!