do a cache clear and reload after saving diary.
I just updated one last night and it worked fine (on a desktop, with firefox browser, w/ ublock origin and ghostery extensions). Always wait for that green message saying "saved" or whatever the actual text is of similar meaning.
at the bottom there's a "revert to old style" ... maybe initiating the editing/adding a week process through the old page style works better? worth a try.
Until then, avoid re-typing stuff. Copy and paste your comment into some txt file and keep your week's pictures/media stashed safely in a folder with it. No reason to re-write everything each attempt. let it simmer for a week and get the kinks worked out.