Can anyone provide some insight into these mutual dreams I have had?

This has happened twice in my life, both times I shared the dream with my sister. Neither dream was quite lucid.

The first time it happened (I was around eight), it was something really trivial. I was bothering my sister, saying the same thing repeatedly. The location was just a room of all white. Later when we both woke up, we discovered we had the same dream (except in hers she was being bothered by me).

The second time (I was around 15) was a lot stranger. We dreamt of being in the same location (it was like a combination of a museum, a box factory, and an airport). We were in groups, my sister being in a separate group from me. I saw her group in the distance; she saw my group in the distance apparently. The major link between our groups was a fictional character (Trucy from Apollo Justice: Ace Attorney, though her appearance was slightly off; my sister confirmed she had the same differing appearance in her dream). Trucy told me she saw my sister in the other group. My sister told me that in her dream, Trucy told her she saw me in my group.

So, is there any kind of explanation here? Has this happened to anyone else? If so, what are your experiences?

Edit: As I explained in a comment, it's very unlikely she's messing with me, as she would correctly finish my sentences while I was describing specific details about my dreams.