Yes, Katyj I have experienced this. First, my mum in the hospital with cancer. I was not there but my sister was. She told me that our mum was struggling to breathe and on oxygen and finally my sister said, "It's okay to go" and our mum reached her hands and arms up towards the ceiling of the room as if someone was reaching down to take her and then her arms went limp and she had left her body. It is really unexplainable but at my home, in my bedroom, I felt her leave us. I got out of bed and walked outside, in the rain, by myself, at night for four hours crying. I won't explain anymore - no point in that.
With my father, I received a phone call that I should visit immediately and so I drove about an hour to his room. I stopped on the way and bought a dozen white roses. When I arrived, he was incoherent although I did visit every week and enjoy his conversation and company. When I arrived, he was on a noisy supplemental breathing machine but he was peacefully sleeping. Like everyone, I didn't really know what I was supposed to do. So, I picked up a book and read the whole book to him. It was a book about the life of Queen Mary. When I was done reading the book to my sleeping father, I opened the window because I felt that his soul needed a way to get out. I said to him, "Dad, it's okay to go now" and I left. After I left, while I was driving home, the care home called to say that he had died. He was my best friend and I never shed a tear when he left. He is not here now and that was twenty years ago, but I feel him every day in my heart and I miss him so much.
Another experience was with my BIL. My DH and I took care of him and after 12 years of fighting cancer, my DH left his brothers bedroom to lay down for 30 minutes in the adjacent bedroom. That is when he left us. My DH still asks me why did he do that??!!?? I agree with others here that no one moves out until we leave the room and/or give the person permission. It is such a strange phenomenon. I won't understand why, until I do it, too.
I am sorry that you are transitioning to a time when your mother is moving on but I am SO happy that she has you to make sure that every detail is as perfect as can be in this situation. Sometimes this can take months. Sometimes it takes days. It happens when it is supposed to happen and I would be so lucky to have a daughter as concerned and helpful as you. Your mother is blessed with your presence, care and concern. My beliefs are most likely far from many others because I am very spiritual and I believe in the afterlife or next life so with that, my thoughts are that your mother is in between our existence and another existence, maybe with relatives calling her to join them but she is unsure whether to leave at this time. I hope that I don't offend you by sharing my thoughts in this matter. They are my own opinions and everyone has their own beliefs and rituals. I think your mum will leave when she is sure you will be okay. Do you have family who will be in contact with you when times get tough? I had no one. It might be a good plan to reach out to a friend who is nearby and let them know that you might need extra visits or wellness checks during this time. When I lost my dad, I got violently ill for no other reason except grief. Keep up on your nutrition, hydration, exercise and peace. Hugs to you.
And more hugs to you.