Changes made to existing books will not be saved. Going to Develop or saving and returnnig to LR shows the same problem. This is with V8.0. Going back to V7.5 shows the bug not to exist. 7.5 works fine in this aea. Windows 10 home. LR Classic CC.
Same problem in Windows 10, LR Classic CC v8.0. Works fine in v7.5; resetting preferences in v8.0 fixes the problem for one extremely small book but not for other books I have tested.
Selecting a different page in the book, making a change to something in the book, moving to another module (eg Library or Develop) then returning to the book module will often initially display the changed page correctly, then after a few seconds the changes are undone and the page displayed changes to the page that was displaying previously.
I have a 2MB test catalog set up that has this problem which I can upload if anyone wants to see what is happening; it also shows a different problem when unable to produce a PDF and how to work around that problem. Of course this was created in v7.5 because I can't do anything with catalogs in v8.0, but both problems occur in v8.0 in this catalog.