I have the same problem as this person who posted on Apple's website:
"Lately, I've noticed that the widgets in the notification center will not stay in the desired order. I arrange them how I like from top to bottom. They stay that way while my MacBook is on. If I restart, the widgets get rearranged into a different order. I have to go back and fix them. How can I get the arrangement to stick after restart? Is there a preference I'm missing somewhere?"
https://discussions.apple.com/thread/7508731?start=0&tstart=0
If anyone knows what the issue could be I would be thankful for a response
"Lately, I've noticed that the widgets in the notification center will not stay in the desired order. I arrange them how I like from top to bottom. They stay that way while my MacBook is on. If I restart, the widgets get rearranged into a different order. I have to go back and fix them. How can I get the arrangement to stick after restart? Is there a preference I'm missing somewhere?"
https://discussions.apple.com/thread/7508731?start=0&tstart=0
If anyone knows what the issue could be I would be thankful for a response