Notes appear to be linked to documents but are not excerpts

I am searching in documents for key words, to enable me to add random, unlinked notes to my child mind map. However some of these random notes appear to be linked to documents when I haven’t excerpted anything. Selecting the note to update/edit it makes the document change away from the document I am reading from. I can’t see any links or excerpts and unsure if it’s me or just a bug. Please can you investigate - hope I’ve made myself clear! I’m on iPad Pro