If figured this out after reading some other posts and thought that this may also help some others.
I have a drawing with a lot of sheets showing manufacturing details.
I use the "replace part/model" a lot. I use this for different variations of a common assembly model.
(I could probably use configurations instead, but find this method more straight forward)
I also copy drawing sheets and replace the existing model with a new one to save time.
Anyways, my issue was that my drawing revisions were not being saved.
I "save" a lot during the day and no errors are reported.
It is not until I want to go home, that I find out that the drawing will not close.
Several times I ended up losing my modifications.
This morning I pulled up the 3 new drawing sheets I created and deleted the "section views"
Then I was able to finally close the drawing and save the changes.
Then I opened drawing again and recreated the sections, as I had them before.